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gj5wuy
|
how Unreal Engine 5 on PS5 can diplay "100s of billions of tris" while my $8,000 PC for 3D animation struggles with these numbers?
|
I understand draw distance and memory allocation and how these objects aren't rendered when not on camera, but I just don't understand how this technological leap has been made possible on a console when I can't imagine having a scene like this in any of my 3D software. Just curious if anyone has better insight to how all this works differently in UE5
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqipobo"
],
"text": [
"We don't have the full technical details yet, so here's some speculation based on what was demoed and what they've said publicly: * Dynamic scaling of asset polygon resolution. It sounds as though that while the actual asset may have enormous amount of polygons, the engine generates an approximation of the polygons based on what the user actually sees. This is more than just what's visible on the screen - it will also have to factor in what level of detail will actually be significant based on how far away the viewer is from an object. * From what they've said it seems they're aiming for artists no longer having to manually generate high/medium/low resolution assets since the engine will scale the high resolution asset at runtime. * Virtual texturing. This technology has been seen before for games like RAGE and DOOM with increasing levels of success each year. The idea is that you can have very large, high resolution textures that can be applied to a landscape/objects. At runtime the engine is then responsible for scaling these textures and dynamically loading/unloading sections of them as needed. These are two big things that stand out to me right now, but there is definitely a lot more going on especially from a lighting standpoint. Plus we'll have to wait and see what actual performance looks like across different hardware configurations. We know from early experiments with virtual texturing that it is heavily dependent on how much data can be streamed to and from the hard drive per second, and then to and from GPU memory, so it can be tricky to get it right consistently. & #x200B; EDIT: Based on some comments made by Tim Sweeney, it looks like they're optimizing Unreal Engine 5's data streaming for the PlayStation 5's custom SSD (Solid State Drive) technology and for NVMe SSDs available for desktop PCs. It gives the impression that if you're trying to load game data from classical hard drives then you may see bad performance."
],
"score": [
19
],
"text_urls": [
[]
]
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|
[
"url"
] |
[
"url"
] |
gj69wd
|
Why are video games developed and rendered in triangles and polygons?
|
Seeing all the new developments in Unreal Engine and the new generation of consoles I’d like to get a basic understanding of what the heck they’re talking about!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqisaug",
"fqisw9q"
],
"text": [
"The game needs a system to describe objects. Say you want to describe a cube, how would you do it? You could say it's a cube with sides a certain length and a center at a given location. But then you need to describe a pyramid. You have to come up with a new way to describe it. Given the variety in shapes that objects in video games have, it's not a viable system. You need some system that can easily describe any object or shape using a common set of data. So they use polygons. You can describe any polygon in space by listing the coordinates for the vertices. Put together an enormous number of tiny polygons, and you can describe any shape or object you want, all using a single system and a series of coordinates.",
"Basically, everything you see on a screen consists of squares. Even circles. We call them pixels. Now imagine you have to fill out the pixels on a model. It's easy to fill squares with triangles on any kind of surface. As an example, try to cover the surface of a balloon with squares - this is not going to work well. However, triangles will fit in there. And triangles are flat. Flat objects require less rendering power which means more efficiency. Lastly, a computer needs to know what shape you're feeding him. We may see that a square is a square because we see squares as a flat object, 4 corners connected with lines. But a computer does not know that. 4 corners which could be connected in many different ways, e.g. a square, a trapezoid or even a pyramid. A triangle however is always flat, no matter how you try to connect the corners. This saves a lot of CPU / GPU power thus again being efficient."
],
"score": [
11,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gjah5u
|
How did we build the first ever precise measuring tool?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqjo56d",
"fqjo3hy",
"fqjocl0"
],
"text": [
"Ancient Chinese had rope with knots at fixed distances. Greeks used their palms. Measuring is actually pretty old but the first ever instrument is unknown",
"What do you mean precise measuring tool? We are constantly building more and more precise tools. The simplest measuring tools predate history though, you can do that by knotting rope at consistent intervals, or using a single object as a reference point.",
"It depends what you mean precise. There were standardised measurements that related to certain set lengths like King Henry I of England fixed the yard as the distance from his nose to the thumb of his out-stretched arm. Once this standard was set you could make \"rulers\" that were this length and from them make others so that you had measuring sticks at every cloth merchant or whatever that needed them."
],
"score": [
6,
5,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjd4lg
|
How does the NSA make any sense of the huge amounts of data in collects?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqk8sby",
"fqk8wna",
"fqkeek1",
"fql9ftq"
],
"text": [
"You're probably thinking of some agent huddled over a computer with the shades drawn, thumbing through individual files one by one. Noooope! With that amount of data the only way to go is to use automated tools to get what they need, and to sort and filter. Kind of like how the post office uses machines to sort letters into neat stacks or into bins rather than having a person look at each address individually; it's the only way with all that mail! One big tool would be a keyword. So as data comes through it's scanned for certain words identified as being important. When one comes up, perhaps it goes to a file, or gives someone in the office an alert. A lot of the data is completely useless to them and will probably be archived away or, more likely, discarded. Two people sending kissy emojis at each other 20 times a day hardly warrants even a passing glance. Perhaps an automated tool could surmise that the owner of phone number 123 and the owner of 456 are in a relationship and Mark that as such if they're keeping detailed logs.",
"Mostly it doesnt. Ok that's not really fair there's hundreds of search filters, analysts and blocks that they have up to make finding what they want easier. But, if you ever want to know why after an attack a news outlet almost always ends up reporting that the attacker/attack was know by the intelligence community beforehand. Well its because they were probably in the system, a big labyrinthine system that buries the data under its own sheer weight",
"They have specific targets they look into that they believe are \"suspicious\" and could potentially hurt the government or the nation in some way- other than that, it's mostly like a data survey. If they find that a bunch of people are using the word \"tomato\" in their communications more than average, they could up the price on tomatoes for better income. Of course they don't care much about tomatoes, but you get my point. Also, wouldn't it be nice to have someone's entire Internet biography in your hands if you wanted to blackmail them or destroy their career? Get them to tell you something? This was a major reason Snowden originally exposed the NSA- because it's so dangerous for them to have access to that kind of power if they wanted to use it. They don't necessarily proactively look through the data, but if they wanted to look through a certain person's data, they already have it stored.",
"The same way as Google does. Two main methods can be used, the first which most people bring up is reactive, or \"after the fact\". For example, you could get a list of all the people that frequent ISIS websites, or Democratic Party ones for that matter. You can also set triggers which warn when someone does something in a pattern that is perceived as dangerous, such as looking up ingredients for explosives. The other one, which affects far more people, is powered by automation and AI. We have programs which can automatically look up patterns in activity that makes you similar to other people of interest. For example it is possible that you order pizza the same way as Bin Laden did. These patterns are also usually incomprehensible to humans, as they are usually purely mathematical. It literally works by dumping a lot of data into a big database, siccing the algorithms on it and getting back a list of \"suspicious people\". There also so-called anomaly detectors, which don't even know what they are looking for, they only give back a list of people who are strange in some way."
],
"score": [
10,
5,
3,
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
gje123
|
- Why does slowing down/speeding up a video make the voices go deep/high?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqkeqh8"
],
"text": [
"Sound waves move horizontally, so when you speed it up it smushes the sound waves together making them have a higher pitch, and when you slow it down it stretches the sounds waves out making them have a lower pitch."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjeudd
|
What is Cloud Computing?
|
When YouTube videos or websites try to explain cloud computing, they just say what server computing is and then say cloud computing ISN'T that. Like I get what a server is- I can picture it- , but you say cloud computing I just can't comprehend. Appreciate any help.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqkmfqo",
"fqkrncy"
],
"text": [
"ELI5: the cloud doesn't exist, it's just someone else's computer. To expand on that topic, cloud computing really is just using someone else's computer somewhere else. For example, say you're doing a large 3D animation and you want it to be done quickly, but your local desktop only has a single, low power graphics card in it. At the simplest way of explaining it, you can go to Amazon and ask to rent a server for an hour. Lets say you want to rent the most powerful one they have, which has 8 Nvidia V100's (~$90k worth of GPUs), 768gb of RAM, and 96 CPU cores allocated to it. You would send your job to Amazon, they process it on that server which is located in their data center, and then they would send the results back to you. It does actually get a bit more complicated than that in that these servers aren't just individual units. Amazon combines the resources of them into a giant pool (or cloud) and when you rent a \"server\", you're actually renting a virtual machine (often referred to as a server instance) with certain resources from this pool allocated to it.",
"ELI5: Typically you buy toys, maybe trike or bike. They sit for most of the time idle and you don't play with them 24/7. You play with them and get bored and probably look to upgrade. Your Grandpa comes and says \"I got 10-20 grandkids, I buy these fun stuff, I will rotate these toys, bikes when they are not in use. You pay a fraction of what it costs you, you don't worry about cleaning, upgrading, maintaining (filling air in bike tires). You just rent from me by the hour. When you are done playing or bored, return back. If you are interested, rent next level toys. Same deal with other grandkids.\" Replace toys with specialized servers, Grandpa with Amazon, Azure."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gjgl5r
|
What is the difference in upload speed and download speed for my wifi?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqkur9k"
],
"text": [
"In the simplest terms, upload speed is how much data per second you can send over the internet, and download speed is how much data you can receive. Good speeds are relative to what you’re use is"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjl71q
|
How does the Color Filter camera in the Photochrom mode on a Oneplus 8pro can see through some plastic/ceramic objects and reveals their internal circuitry? (with examples)
|
[Example #1]( URL_0 ) [Example #2]( URL_1 ) [Example #3]( URL_2 ) [Example #4]( URL_3 ) & #x200B; This is the most amazing hidden application on any smart phone in the market and I am sure even Oneplus did not expect it to work this way. Can anyone explain to me how this work? & #x200B; Thanks!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqlip9p"
],
"text": [
"The OnePlus 8 has an additional camera sensor that is in black and white, but it is also sensitive to infrared, this sensor assists in low light photography. There was a post on r/blackmagicfuckery that showed a OnePlus 8 seeing through an Apple TV. The Apple TV has plastic on the outside that is transparent to infrared, so it's remote can communicate with it. The concept is similar to X-Ray photography in a dentist's office. X-Rays are just light but with a lot shorter wavelength (and higher energy) than what we can see. X-Rays can pass right through skin, muscle, and tissue but can not penetrate bone. This can be attributed to density or other chemical properties. Someone in the comments of the post mentioned above said that the transparency was due to polarization but I debunked that [here]( URL_0 ) Long story short, some things are transparent to certain wavelengths of light and some aren't."
],
"score": [
6
],
"text_urls": [
[
"https://www.reddit.com/r/blackmagicfuckery/comments/gjbdt6/oneplus8pros_color_filter_camera_can_see_through/fql1slk?utm_source=share&utm_medium=web2x"
]
]
}
|
[
"url"
] |
[
"url"
] |
gjlvxl
|
Unreal Engine 5 looks amazing but it does not look exactly like real life or that it was shot with a camera in real life. What are we missing and why is that not possible yet?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqloba9"
],
"text": [
"In short - computation power. When movies and shows render really high quality graphics it takes ages to render a single frame. Video game engines need to be real time for gameplay which is typically around 60 frames every second. There are more complications for life like rendering but these challenges are slowly being conquered"
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjm0kg
|
What is a video game engine?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqlne4i"
],
"text": [
"When you develop a game there is a lot of stuff you need to program, and a lot of that stuff is needed for pretty much any game you might make. For example you need code that draws models, plays sounds, takes controller input, plays animations, simulates physics, online communication for multiplayer, etc. There's no point in writing all that stuff from scratch for every game. So instead you can use a game engine. A game engine is a framework for making a game that already has the ability to do all that stuff. So you just need to concentrate on the specifics of your particular game. For example say you want to put a bouncy ball in your game. You don't need to figure out all the maths and write code to simulate a bouncing ball. You just tell the engine that you want an object with these physics properties, this model, it plays this sound when it hits something. And then the engine handles it for you. Usually a game engine will also includes game development tools for you to be able to create levels and author all kinds of other content for use in the engine."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjoksu
|
Whats the difference between a wifi router, a router and a modem?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqm3si5"
],
"text": [
"A router is a device that lets you connect several devices in a local network. A wireless router is the same thing, except that the devices connect to it worelessly (although it usually contains a couple of ethernet ports). A modem is what connects you to the internet. Some modems also functions as routers, so you don't need two separate devices. What you want is a wifi extender."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjpsa7
|
Why is a games source code being leaked a bad thing? Doesn't all that code exist in the games files?
|
I do know that that code obviously then inst available, since that's why the recent leaks are significant...but why is it significant? Obviously cheaters will use that to more easily make hacks, but why is that code not part of the game? How does that code not exist in the game files? Is it hidden in some way or is some of that engine code or what exactly is it?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqmax0k",
"fqmc4d0",
"fqodg42",
"fqmcami"
],
"text": [
"Because the executable files that you have are in machine code, and is unreadable by humans. Even if you converted it back to human-readable code (with a decompiler), there are probably thousands of variables which are completely unlabeled, which you'll have to figure out one by one. And if a programmer used any unorthodox tricks, you'll have zero chance of figuring it out.",
"You run the source code through a compiles to create the machine code that the program run. There is no simple way to go backward in some way it is not possible at all because stuff that we use to understand the code is no longer there. An integer name HitPoints is easy to get what ís is but in the compiled code you just know that there is an integer used in a memory location like $85004F3C You can create code in high-level language from the source code but the name of everything is gone so you have no idea what you look at and what it might do. So to say that it takes 100x longer to understand the code is not a bad initial estimation. So the source code is like the recipe for a dish with all instruction quite easy to understand and the machine code is the dish itself. You could from the try to understand exactly how it was done but it is a lot harder.",
"It's the difference between eating a cookie and having the recipe. If you eat a cookie, you can probably figure out some of what's in it, based on common ingredients cookies have and what you're tasting. But you won't have the exact proportions and you won't necessarily know whatever secret ingredient makes *this* cookie have its exact taste and texture. But if you get the recipe, you can make the cookie, or even make your own modified version. In a similar way, compiled code is very hard to pick apart into exact logic of the game. You can do it, but it's hard to follow. The source code, on the other hand, is like the recipe that makes the executable. It's usually written in an easy-to-understand way, and if you have the source code, you can make modifications and then create your own executable with your changes. You could also figure out places that the standard copy could be manipulated while running more easily, allowing you to make cheats. You could use it as the basis for an entirely new program with very little effort compared to writing your own from the ground up.",
"When a developer works on a game typically they'll be writing the source code. The source code they work on is designed to be human readable and easier to edit. It would normally use english (or whatever other language) words and decimal numbers. Like a line might have something like if x==10, y = 5; which is easy to look at understand. If some variable X is equal to 10, then it assigns the variable y a value of 5. You, as a person, can look at that and understand what's going on, and if you decide you want to look out for when x is equal to 9 instead then you can make that change easily. The problem is your computer or console or whatever doesn't read english. 'If' doesn't really mean anything to it, it only speaks in bits and logic gates. So you have to compile the code into something your computer can use. This changes your easily readable source code into more complicated object code that your computer can use as actual instructions. A person could not just glance at object code and figure out what's happening, and you can't really go from object code back to source code. The object code is what normally ships since it's what the game needs in order to actually work, and this protects the source code. It makes it harder to find exploits because parsing through object code is a nightmare for a person. But if your source code gets out then a person can go look through everything and would have a much easier time figuring out how the game works and finding ways to exploit it."
],
"score": [
21,
13,
3,
3
],
"text_urls": [
[],
[],
[],
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|
[
"url"
] |
[
"url"
] |
gjq1qx
|
www is no longer required before a website name. Why?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqmctao",
"fqmd1jb",
"fqmd50g"
],
"text": [
"It never was, it's just a convention. Each subdomain can go to a different IP address, so for instance back when FTP was still commonly used you could have URL_1 and URL_0 being handled by different machines.",
"It never was required. It was just common practice to do so back in the day but over time people have dropped the practice as it's not necessary. In the olden days of the internet domains would separate their services in to multiple servers like URL_1 URL_2 URL_3 URL_0 etc.",
"It was never required just the common way you set up addresses to the server where the www subdomain was the webserver. So was the common way to set up stuff when WWW was new and not the primary service on the internet. The address to the first web page was for example [ URL_0 ]( URL_0 )"
],
"score": [
17,
8,
5
],
"text_urls": [
[
"ftp.example.com",
"www.example.com"
],
[
"www.foo.com",
"smtp.foo.com",
"ftp.foo.com",
"gopher.foo.com"
],
[
"http://info.cern.ch/hypertext/WWW/TheProject.html"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjqrpk
|
how can LED screens be organic/OLED?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqmh81q"
],
"text": [
"The chemicals used are organic chemicals (as in organic chemistry vs inorganic chemistry class). It's not organic as in the \"organic vegetable\" use of the word."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjt7ys
|
Bellsouth/atlantic turned into AT & T & Verizon?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqmyanu"
],
"text": [
"In 1984, ~~the Supreme Court ruled that the AT & T Corporation was a monopoly~~ the US District Court for the District of Columbia presided over an antitrust settlement between AT & T and the Dept of Justice that confirmed the AT & T Corporation was a monopoly and forced it's breakup into 8 regional telephone companies. Those were: AT & T, BellSouth, Ameritech, Pacific Telesis, Southwestern Bell, Bell Atlantic, NYNEX, and US West. Through a series of mergers over the last 35 years those 8 companies have been whittled down to 3 companies: * AT & T (formed from the remnants of AT & T, Southwestern Bell, Telesis, BellSouth, and Ameritech) * Verizon (formed from Bell Atlantic & NYNEX + some non-AT & T telecomm companies) * CenturyLink (formed from US West + some non-AT & T telecomm companies) Interestingly, the AT & T we have today *isn't* the original AT & T that came out of the break-up. That AT & T went under, was acquired by Southwestern Bell, and Southwestern Bell (at that time known as SBC Communications) changed it's brand from SBC to AT & T (since that brand had more mind-share). Even more weirdly, the original name for AT & T in the 19th century was . . . yep, you guessed it, Southwestern Bell. So Southwestern Bell became AT & T which later got split into AT & T, Southwestern Bell, and six other companies. Then *that* Southwestern Bell bought the remnants of *that* AT & T and re-named the new combined company back to AT & T. Clear as mud! EDIT: corrected the court system that managed the case."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjtphw
|
How can a printer print a document so fast without the page looking messy?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqn0xu3"
],
"text": [
"The ink is designed to absorb into the paper quickly. Also it does help quite a lot that the head does not physically touch the paper, it just comes very very very close to it."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjuwbq
|
How would any government agency even obtain a user's "browser search history"
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqn7mh0"
],
"text": [
"They don’t get browser history, they get browsing history - they contact your ISP and get their transmission logs."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjvdk9
|
Why is Bluetooth audio so unpredictable? Some times you can listen to music from seemingly impossible distances, when other times just moving your hand near your device causes an interuption.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqncr61"
],
"text": [
"That's just how digital transmission works. Data is sent with some amount of error correction, which allows for let's say 5% of data loss. Right until 5% the quality is going to be perfect. The moment that is exceeded, error correction fails and you have a gap in your audio. With wireless transmission there's all sort of interference from walls and other devices, so even small changes in positioning can be what sends you over the edge, if you were already close to it. It works the same over copper which is why premium HDMI cables are nonsense -- it either works perfectly, or it works very badly or not at all. If a cheap cable works as it should a more expensive one isn't going to gain anything."
],
"score": [
12
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjx76a
|
how laser eye surgery fixes astigmatisms and how it works so fast
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqnqfbn"
],
"text": [
"As I understand it, astigmatism is due to a malformation of the cornea. The laser goes in, and removes some of the tissue in order to reshape the eye essentially. Thus due to no longer having a wonky shaped eyeball, vision improves."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjxpn7
|
With Youtube servers down at the moment. What does getting them back 'up' really entail. Is it a large team working on bugs? Or just one or two head technicians with one issue that they need to resolve?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqnqgpq",
"fqnq4ht"
],
"text": [
"Usually, the main issue when something is down is not fixing the issue, it's figuring out what the issue exactly is. Deploying the fix is usually something that takes a few minutes, but figuring out what the fix is can take hours. Usually, software developers (the guys who produce and eliminate bugs) are not involved with server outages. Server outages happen either because of hardware failure or because of a bad configuration. So I assume that a lot of technicians are currently checking all their systems to figure out where the bad hardware or config is. This usually involves checking status monitors, reading log files, and doing simple input/output tests of all components involved, until you find the one that is misbehaving. There are a couple of exceptions to this, but this is the most common scenario. For instance, it gets a lot worse if stuff hasn't just stopped working but produced \"wrong\" data for any length of time before somebody noticed. Then you need to undo the wrong data, which can take very long, and you need to figure out whether it's safe to bring the service back online or if that would make things even worse.",
"It's most likely a decent sized team troubleshooting back and forth from technicians from multiple areas of expertise including servers themselves, physical teams checking connections, checking software, etc...."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gjzun0
|
How were credit checks run in the days before internet/computers?
|
Nowadays it’s pretty simple for a car dealership to run a credit check or to apply for a credit card, but how was this done and where was this info stored in the pre-information age?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqo3jfo",
"fqobci1"
],
"text": [
"They called a phone number and told them your info and they got credit info back. Before that it was a mail based process. Before that it was all based on whether the local bank would lend to you. Because they knew you and knew your income.",
"Before computerization most banks were small and local. The Bank Manager and/or if the bank was larger the Loan Officer attended Church, joined the Rotary Club (or the Elks, or the Moose Club) and usually knew people or could find out about people’s “reputation in the community”. It was considered to be a simple fact that people who attended church regularly were better credit risks. He could call the local police and see if you had any record, and call the gas company and your landlord to see if you were paying on time. He’d also call your employer and see how good your “Chances of continued employment looked.” For a big loan he might like to meet your spouse as that was also considered a good indicator of your stability and judgement. Then, the Bank Manager would make the decision based on this gestalt impression of your likelihood to repay the loan. If you were young but had impressed everyone in high school he just might take a chance on you despite having no credit history. It was purely a judgement call based on experience with little statistical basis. As computers became available, it was possible to gather large amounts of data and start to discover statistical correlations. Additionally as small town America grew up, it became harder to know or find out about people well enough to make a good decision. So, statistical models were built and Loan Officers’ decision authority faded away. This modeling system allowed banks to operate loan businesses in areas where they did not have local knowledge and ultimately killed almost all small local banks."
],
"score": [
7,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gk1ivn
|
why were playstation 1 CD's black and playstation 2 CD's blue, instead of looking like regular CD's? How did that work with manufacturing and reading the disc, and why were they designed like that?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqozhut"
],
"text": [
"It was purely cosmetic, to look distinctive. The dyes were chosen to not interfere with the lasers used to read the discs."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gk4hp7
|
how does SpaceX get money? Who pays SpaceX to fly things off the earth?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqoyu57",
"fqp4wd7"
],
"text": [
"Quite a few. You can look at the [list]( URL_0 ), but the short is: * SpaceX themselves for testing * SpaceX for Starlink * NASA, for space missions (including supplying the ISS) * Telecommunications companies * Other aerospace companies * The US military For some specific examples, a GPS statellite was put in orbit by SpaceX, and they did multiple launches for Iridium, a company that provides satellite based cell service that works in places like the middle of the ocean or uninhabited places.",
"Thats not really a SpaceX-specific question. Gouvernments need rockets to launch a lot of stuff into space: Military stuff (like spy satellites), stuff that provides infrastructure (like GPS satellites) and sciency stuff (like space telescopes or mars rovers). Companies also need rockets to launch their stuff, which in their case is mostly about communication (like those satellites that all those satellite dishes are pointing towards). And since huge, expensive rockets are still the least crazy way we have to get stuff into space, they have to pay loads of money for that service. If anyone ever finds a practical way to reach space with a railgun or a scramjet or whatever, rockets would probably be obsolete immediately."
],
"score": [
7,
3
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/List_of_Falcon_9_and_Falcon_Heavy_launches#2010_to_2013"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gk5356
|
Why can't programs run .zip files although they take just a few seconds to extract?
|
Title, really.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqp0eso",
"fqp1irj",
"fqp2nod",
"fqp4wgf"
],
"text": [
"I think if you wanted you could programm them to be able to. However that would mean that your programm would have to extract the whole zip-file each time it needs one of the contents. Thats a lot of computational power and time wasted. The only benefit of it running off of a zip would be slightly faster integration of that file once, but having to run off a zip would cost you every time you used the program",
"A zip file is a file. The program has no way to know what it is. If it does, and the programmer decides to support it, then the program could easily read it, decode it and run it. There are plugins that allow a zip file to look like a disk drive to other programs. Then a program can do exactly what you want.",
"It is the same as a book actually. You get a book for your birthday but it is in a nice birthday box. You want to read the book but you have to unwrap it first which only takes a second. Also the compression methode changes the binary code of the program. A decompression program has to reconstruct the full binary strings of the files inside the ZIP to make it back to the origional state it was before compressing the data.",
"It's like sending your tax return, or a complaint letter, written entirely in shorthand. Of course the people the other end \\*could\\* translate it and then act upon it if they really wanted to. Maybe some would. But it's not up to them to do so. A PDF program is expecting a PDF (which is usually already \"zipped\" inside itself!), not a ZIP. If the programmer decides to write the logic to also open ZIPs, extract them to a temporary location, look for PDFs inside them and then open that PDF from the temporary area, and then clear that all up when you're \"done\" with that file, then fine. (Don't even get into what happens if you have a filetype that you want to modify then save back into the ZIP). But it's not necessary, so it almost never happens."
],
"score": [
5,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gk6vqj
|
What does RAM do In a pc and how much is needed for high-end gaming?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqphvcz",
"fqpc0rl"
],
"text": [
"Think of your hard drive as a series of bookshelves. You can't read a book on the shelf. Instead you take it to a reading table (RAM) and lay it open to read it. The more RAM you have the bigger the table and the more books you can have open at once. If the table fills up, you have to return a book to the bookshelf before you can get to another. Some games might need you to read 4 books at a time, others might need 8 to get the information fast enough.",
"If you want high end you should go for at least 16gb, 8gb works for the most part on current games but newer games will most likely require more ram. 8gb won't get you high-end pc anymore. You should also look att the speed of the ram and not just the gb."
],
"score": [
11,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gk7znw
|
Why does turning something off and on fix problems?
|
I know it works most of the time with my pc and my smartphone, but yesterday at the dentist a drill didn't work correctly, so they turned the entire chair and all the appliances connected to it off and on and the drill was working again. Why does this fix so many problems when nothing is changed in the hardware itself?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqpfsop",
"fqpobe9"
],
"text": [
"it resets the software. pc,phone and even the chair at the dentist all have some form of software on them. If it is a problem with the software a reboot resets it and hopefully it starts to work as expected again.",
"* Turning a device off and then back on is like swatting a fly. * It doesn't solve the root problem of the fly. * It just makes the fly go away for some time. * Maybe the fly comes back, maybe it doesn't. * The reason for this is because there is a flaw in the logic programmed into the device or software. * Most of these flaws are caught with testing before the device/software is released. * But some flaws only popup when there is a very specific set of conditions and testing for every combination of possibilities to reveal these conditions is hard and time-consuming. * Re-starting the device clears anything in memory and start the program over from the beginning. * So it doesn't stop the flaw from existing, it just resets the conditions that can cause the flaw to be a problem."
],
"score": [
7,
7
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gk8rmc
|
Why are FM stations odd decimals and AM stations whole, even numbers?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqpl9ek",
"fqpvq4f",
"fqpvup0",
"fqpt3bx"
],
"text": [
"The FM radio band is 88.0 MHz through 108.0 MHz. FM radio stations are 200 kHz wide (0.1 MHz on each side), this is the bandwidth that carries the signal(and associated sidelobes) If you were to put an FM radio station at 100 MHz it would interfere with everything from 99.9 MHz up to 100.1 MHz. This is alright at 100 MHz but if you put that same station at 88 MHz its now interfering down to 79.9 MHz which is outside of the FM radio band. That could interfere with VHF TV broadcasts or other things in the VHF band that may not have the power to fight an 80 kW FM transmitter. We separate the RF spectrum into bands assigned for certain purposes and its important to keep each purpose inside its own bands to avoid disrupting other services",
"AM is typically broadcast in the Kilohertz range, while FM uses the higher Megahertz ranges. If we presented the channels using the same unit, you would have silly things like 0.8 AM (instead of 800 AM) or 97700 FM (instead of 97.7 FM).",
"A simple piece not explained so far, units matter. FM stations are described in MHz (MEGA-hertz, or million hertz), while AM is described in KHz (KILO-hertz, or thousand hertz). They both are in hertz, but the decimal point is moved three places. So, an AM station, let’s say 680 KHz, could also be described as 0.68 MHz. Or conversely, FM station 102.3 MHz could also be called 102300 KHz. Both of these sound weird, but are accurate. Hopefully that explains the decimals vs whole numbers. See the other comments for odds vs evens.",
"FM radio ranges between 88.0 MHz and 108.0 MHz. It has to be between those values and not equal to those values, and it's is regulated by FCC (at least in the US). Radios have a buffer of 0.1 MHz, so you can only put a radio station every 0.2 MHz. Having an odd number allows us to squeeze in one additional station. Ex) If we range between 0 and 1.0, with even numbers we can use 0.2, 0.4, 0.6 and 0.8. Because remember we have to be between 0.0 and 1.0, never equal to. So we get 4 stations with even numbers. With odd numbers, we can do 0.1, 0.3, 0.5, 0.7, and 0.9. Which is 5 stations. This only explains why FM is odd, I'm not sure why AM would be even. Also, I have no source for this, an electrical engineer friend of mine told me this a while ago."
],
"score": [
35,
11,
8,
4
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gka3pl
|
How do they make the sun or fire or other effects look very bright on TVs and monitors?
|
Mostly during videogames as compared to TVs or movies
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqpt5pm",
"fqq8x1b"
],
"text": [
"One thing they will often do is darken the surroundings when a bright light source comes into view, creating greater contrast. The same effect also happens in many real cameras which can auto adjust exposure based on the light level.",
"In real life when there is something very bright, your eyes can make it look like there is a glow around it. For example, someone points a small bright led flashlight at you, the glow is bigger than the light source. This glow is sometimes captured by the camera, other times its not, and they have to use special effects to add in the glow, or to make it look brighter."
],
"score": [
8,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gkaguy
|
With cosmic ray soft errors occurring quite often, how comes my non-ECC RAM/SSD doesn't lead to blue screens at all?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqpvkz9",
"fqpvsnb"
],
"text": [
"Statistics are your friend here. In 1996 IBM estimated 1 soft error per month per 256 MB of RAM. If you've got 8 GB of RAM that means you should expect a single soft error per 22.5 hours of run time. Most of your RAM isn't doing anything important most of the time, if you assume that 70% is used for precaching data that'll get thrown out then you're down to a single soft error in a section that matters every 67.5 hours. Now what are the chances that even in that sector that matters that you'll get that error and read from it before it gets overwritten again? The end result of all this is that while you may get 1 soft error per day, it is extremely unlikely to impact a critical section of RAM mostly because most things in RAM aren't critical to the OS operation. You'd have to time and target your bit flip extremely well to cause the OS to crash due to cosmic rays Now that isn't to say it doesn't happen. I guarantee someone in the world had an unexpected crash of some system due to a bitflip from cosmic rays, but the chances of it happening to your system while you're using it are quite low",
"a) the error rate is low, perhaps one error bit per month per 256 Megabytes of ram b) not all errors are bad. If you have an error in code that doesn't get executed or stack space that's not in use (so it's written again before it's read) - no harm no foul. c) even bad errors don't need to cause BSOD. Turn an \"a\" to a \"c\" on some help screen, even if the user sees it it's a typo, not a processing fault. Similarly, even changing an executable instruction (from an ADD to a SUB) might give the wrong answer but not cause the program to die. d) Even if an error occurs, the OS tries hard to clean up or terminate the bad process without crashing the whole OS. The OS code is a smaller part of memory than it once was, as memory gets bigger. BTW, I doubt you have non-ECC SSD, that sort of thing is pretty standard in SSD controllers."
],
"score": [
8,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gkc5u0
|
How Hardware and Software communicates?
|
I still wonder how people manage to create a machine that visualize a graphic to a screen then commands it with a button. I still wonder how "programming" works through metal/gold/copper I'm still amaze that people made these stuff
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqq8p9x",
"fqq7fyo"
],
"text": [
"The software is a bunch of electrical charges arranged inside of the hardware. It's not necessarily \"communicating\" to the hardware as much as it's what's going on inside of the hardware at a given moment. If you want to get a grasp of what's happening, it's best to ignore the fancy \"how does it make this fancy spreadsheet or play Skyrim\" and go back to basics: How do we get a computer to represent numbers and do basic stuff with them like adding? Once you see that it's fairly easy to imagine how that scales up. A very simple demonstration is made [in this excellent video]( URL_0 ) that demonstrates how you can make a basic calculator with dominoes. It's the same principle as a computer uses, but it replaces transistors (little electrical switches) with dominoes knocking each other over. It doesn't demonstrate all the complexity involved in a full computer, but gives a good flavor of what's happening. If you have a few hours to burn and know how breadboards work (a pretty easy thing to look up on Google or Youtube) you can watch Ben Eater demonstrate [how to build an 8-bit computer from scratch in this playlist]( URL_1 ). If you want to see how that translates to displaying graphics on a monitor he has a short series where he shows how to build a simple (and not very good) video card in a short series that begins with [this video]( URL_2 ). The tl;dr of the series is that there are instructions that can be hard-wired into the CPU, which we represent as binary numbers. That number is represented by either having voltage on a wire or not, so a 4-bit number might be hot, cold, hot, cold (1010 or 9). When those voltages are applied to the CPU wires it triggers the hardwired arrangement of transistors to execute whatever the 1010 instruction is, which the CPU manufacturers have determined. This works just like the dominoes example I explained earlier. You're telling the CPU to \"knock over that particular arrangement of dominoes\" which then turns on some arrangement of output wires from the CPU that gives you the answer to your math problem or sends a signal to some other part of the computer to do something. The input wires from the CPU are connected to the RAM chips (actually a bus on the mobo I believe, but let's keep it simple). The RAM is holding the series of instructions as charges inside of capacitors (or other methods, again keep it simple). Those charges in the capacitors *are* the software.",
"It really comes down to two basic concepts: 1. You can represent any piece of information as a number as long as we all agree on a system for mapping those numbers back to their information. For example, if we all understand how to represent a color as numbers, and we all know how to signal that this specific number represents a color, so decode it as such, then we can easily communicate colors with numbers. This goes for everything: letters, pixels on a screen, sound, locations on a storage medium, etc. 2. You can represent any number in binary, and by extension in electrical circuits by something being in opposite states (e.g. high or low power). So then it just comes down to sending a bunch of instructions to a processor on how to move and transform data really, really fast so that it appears as if it's happening instantaneously. You can imagine circuits as a series of train tracks that control the levers of other train tracks. If a train is on track A, it might control whether another train goes down track B or track C. All of this gets orchestrated so that the right trains end up at the right destinations based on a handful of initial trains, such as the ones stored in your hard drive, or sent from your keyboard."
],
"score": [
13,
5
],
"text_urls": [
[
"https://www.youtube.com/watch?v=lNuPy-r1GuQ",
"https://www.youtube.com/playlist?list=PLowKtXNTBypGqImE405J2565dvjafglHU",
"https://www.youtube.com/watch?v=l7rce6IQDWs"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gkgm28
|
How is it possible that Next Gen Graphics Engines can render billions of triangles, dynamic lighting, DOF etc at 60fps+ but making a single frame with similar settings in a 3D rendering program would take minute to hours to render?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqqyqym"
],
"text": [
"Basically graphics engines take lots of shortcuts. When you're looking at a rough surface, is it really rough? Or is it just a texture of something rough. Far away objects are reduced in complexity, which you don't notice (because it's far away), but it's there. A proper 3D rendering program sends light from a light source, reflects it in all directions, and records what hits the camera, just like in real life. This is extremely time consuming and you're spending a lot of time tracing rays that, well, you never see."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gkjmgz
|
What’s the difference between regular/studio recordings of songs and Mono versions?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqrh19x"
],
"text": [
"Mono is the same sound coming through both sides, both earphones, studio is recorded stereo with different sides having different sound potentially. Queen likes having different sounds coming through different ears (“little high, little low” from bohemian rhapsody) and if it was mono that effect would be non existent"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gkkpv4
|
Why 5G towers and remotely read electricity meters and the EMF they emit are NOT dangerous.
|
I don't believe they are, but I'm after a convincing argument to use with those who do, that isn't condescending and they might consider. I work for a power company and get a lot people complaining that they don't want one of those remotely-read (via cell network) electricity meters so close to their kids' bedroom because of "the harmful EMF from the meter".... (while calling from a mobile phone, in their home, which surely also has wifi and a microwave oven). Correct me if I'm wrong, but this is tinfoil hat shit, right? I know about ionising vs non-ionising radiation, and my understanding is that therefore the EMF these people complain about is harmless and their claims that their kids "have a condition that makes them vulnerable to EMF" are bullshit. I need to know how to explain this kindly, and hopefully turn a few conspiracy theorists and technophobes. Googling it just gives me questionable articles that suggest maybe there is some danger. I need cold, hard, truth about why your precious kiddos aren't in any danger from you installing a smart meter.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqs6mht",
"fqrxijx",
"fqrogh4",
"fqrz80s",
"fqsxgpp"
],
"text": [
"There's two types of electromagnetic radiation (EMF): Ionizing and non-ionizing. Ionizing waves have high energy and a short wavelength. Since their wavelength is so short, they can interact with matter on the molecular level. A photon, a packet of light energy, will sometimes collide with an electron and knock it off its atom. This results in the atom having a net positive electrical charge. This slightly changes its chemical properties and can cause DNA molecules not to replicate properly, increasing the odds of cell going cancerous. The immune system is pretty good at dealing with a few cells that mutate like this, but enough exposure overtime will increase the likelihood of developing a tumor. The high energy of the photons can also cause burns. Ionizing electromagnetic radiation includes ultraviolet light, x-rays, and gamma rays. Non-ionizing radiation is exactly what it sounds like. They have low energy and long wavelengths. Too long and too low to knock the electrons off their atoms. Though it can cause regular old burns if concentrated in one spot, by say a laser or microwave oven. Non-ionizing radiation includes radio waves, microwaves, infrared radiation, and visible light. 5G operates in the microwave band, close to the frequencies used by WiFi routers. These devices use relatively low energy that's spread out over a wide area. So where as a laser focuses it in one spot, these are more like a light bulb. There is no known health risk associated with it. Any claims otherwise is strictly psudo-science. It's also worth mentioning that you are constantly surrounded by both natural and man made magnetic fields. The Earth generates a pretty darn big one. High energy particles also continuously bombard us from space. Any time you run current through a wire, you also generate a magnetic field. The more legitimate concerns over 5G are security related. Much of the infrastructure is being manufactured by Huawei, a company that has direct ties to the Chinese Communist Party. So there's worries it could be used to bug the telecom systems of rival states. But that's more a geopolitical concern than one that's going to affect the average users. At least in direct terms.",
"Remote read meters usually just have a sim card in them that the meter operator dials up every time they want a meter read. Essentially it is exactly the same thing as a mobile phone. So if your compatriots are scared of EMF, then ask them if they are scared of their phones. It is the exact same thing.",
"The sun and phones/ computers/ Samsung Smart Fridges they're Facebooking from expel more radiation than 5G towers. EMF does the same. I don't know how it works, but 4G towers have been around since, what, 2014? 2013? We've been fine since then, our brains haven't melted from the radiation, we haven't turned into a Cueball from Doom Eternal. We are ok. I'm typing this on 4G right now.",
"From what I understand there are two types of risk with radiation, heat and DNA damage. Technically, 5G will heat you up by the same mechanisms that occur in a microwave, but even if you hug a 5G tower it's won't be dangerous heating . Maybe don't hug one for hours. This heating effect diminishes [greatly over distance]( URL_0 ), so if you are 1m from a tower, and you move to 2m from the tower you are getting 1/4 of the radiation, 3m and you're getting 1/9, 4m = 1/16. By the time you're 10m away you're only getting 1/100 (or 1%) of the radiation. Because your phone is right up against you, and the tower is some distance away, your ear gets much, much more radiation from your phone than from the tower. DNA damage is caused when **ionising** radiation causes breaks in the DNA strand or knocks genes out of the strand. This is the type of radiation uranium and the sun give off. 5G is **non-ionising** radiation, so there aren't particles flying out of the tower to smash into your DNA. There have been [25,000 studies]( URL_1 ) into the health effects of non-ionising radiation and evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields.",
"My time to shine, I used to call people to arrange smart meter installations, and was consistently the highest performer, so I know a little about objection handling smart meter concerns. Most smart meters when I was doing it were SMETS 1, or first generation, which was much easier to allay any fear. They literally just send a text message once per day to the energy company with the meter readings. You could just point out that it's the exact same thing as them sending a text message with their readings once a day, only the box does it all for them and they never have to go anywhere near it. It always helped if they were taking the call on mobile as their phone was sending the equivalent of more than a years worth of readings in signal/radiation just in that one call alone. SMETS2 is different, it's more akin to WIFI at times, and 4G at other times. They came out in 2018 in the UK, and unless they've updated since I left the job, they don't use 5G. Half the country uses radio signals (as in the thing that's been around since the early 20th century) and the other half uses the cellular network (probably 4G, possibly 3G or GPRS, I can't remember). They then communicate locally with other smart meters in the area like a local wifi network to improve overall signal. SMETS2 is sending and receiving more data than one SMS a day, but it's still not much. Basically if the person is happy watching Netflix, they're already sending a ton more data than a smart meter ever does. I think it uses about the same as browsing a site such as Facebook (that sends and receives data frequently). If they're a complete technophobe and don't have any devices at all, it's a tougher sell, but the fact is if they don't have a smart meter, at least one of their neighbours probably will, or if not somebody in their area is likely to have a WIFI router. Radio waves are everywhere and have been for a long time. If they start on a rant about how microwaves cook food, I used to let them know it's all about the wattage. Microwave ovens operate at 500 - 1000 Watts. A 1000W lightbulb will incinerate food, but a little LED drawing a couple of watts won't even get warm. Same applies to any band of the EM spectrum. I occasionally would make reference to the big ball of radiation in the sky, which emits everything from UV, down to radio waves. I'd usually manage to talk around anybody who wasn't a complete \"EMF sensitivity\" loony. 5G wasn't really a thing back when I was in the job (and Smart Meters don't use it) but most of the same principles apply. It's electromagnetic radiation, it's extremely low power, and we've been surrounded by WIFI devices that use similar frequency bands for years now. It's even closer to visible light than 4G is (not that that means much). It isn't ionising radiation"
],
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13,
9,
8,
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"https://en.wikipedia.org/wiki/Inverse-square_law",
"https://www.who.int/peh-emf/about/WhatisEMF/en/index1.html"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gkljl1
|
How do you get stereo sound out of a vinyl record?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqrso0r"
],
"text": [
"Picture each 'groove' in the vinyl record as a valley. The etching on each side of the groove differs. The right side of this \"valley\" is responsible for R-input, the left-side of the 'valley' is responsible for the L-input."
],
"score": [
4
],
"text_urls": [
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|
[
"url"
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[
"url"
] |
|
gkoft9
|
Why can phone cameras not take good photos of the moon? They always seem to make it 10x smaller than you can see with the naked eye.
|
Technology
|
explainlikeimfive
|
{
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"text": [
"The human eye is close to a 35mm lens or focal length. The standard phone is 12-15mm until zoomed in. Some light reading on [focal length ]( URL_0 )",
"The naked eye is very powerful. Especially in low light conditions our eyes are very good at adjusting to it so we can see better. Also when you have the whole sky around the moon it’s hard to realize the actual size and most people overestimate how big it looks.",
"The moon is always approximately the same size to us, but it is a small part of the total night sky. Your mind tends to mute out the uninteresting blank sky and focus more on the moon so it seems more predominant than it actually is. When you take a photo of the moon with your camera, it gets the rest of the night sky in the shot. When you look at your phone's picture, you see the moon, the night sky, the phone, and everything else around your phone to really put the moon to sky ratio to scale. When you're just looking at the moon, there is no other reference point to appreciate how little of the night sky it takes up.",
"There is also an interesting optical illusion that goes on with the moon. When it is closer to the horizon it looks immense but when it reaches its apex in the night sky it appears much smaller. You can use the quarter trick someone else mentioned to confirm it is indeed the same size. This happens because when the moon is in the middle of the sky you brain has nothing to compare it to, but when it's near to the horizon you do.",
"The zoom functionality of a camera to achieve 10x zoom is based on a 'digital' zoom. The software resizes the image taken by the sensor on the camera to provide a close up look. Cameras are limited by the sensor pixel count and the lens on the camera (which is typically in the 26-35mm focal length). Where you need a lens with a 400-1000mm focal length to achieve 10x zoom of the moon. Fitting such a large lens will be difficult on a phone camera.",
"One phone brand tackles this in a unique way. Some Huawei phones (the higher end models at least), will use the ai chip to fill in detail. So, if you zoom all the way in on the moon, it'll use server side mapping of the moon to create super high detail including craters and dark patches. I tested it out on my Mate 30 Pro and it created a pretty awesome picture of the moon.",
"Aren’t you experiencing an optical Illusion when you look at the moon? Your brain makes it seem bigger due to objects in the foreground, remember hearing or reading that somewhere"
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"https://www.nikonusa.com/en/learn-and-explore/a/tips-and-techniques/understanding-focal-length.html"
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|
[
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[
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|
gkpidg
|
Why do phone calls always sound bad regardless of how good your microphone quality is?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"A lot of it has to do with Quality of Service (QoS) characteristics based on the traffic profile you're exhibiting. In earlier generations, e.g. GSM (2G), the networks exclusively used really low sample rates to encode audio data. The result, humans can still understand your voice while underlying data gets \"highly compressed/quantised\". Im later generations, UMTS/LTE/NR (3G/4G/5G), more onus has been placed on QoS characteristics, e.g. creating channels based on the type of traffic you are sending? For example, voice traffic (real-time data) doesn't degrade much if you loose a bit of data here or there. Where as latency and out-of-order arrival absolutely destroy the quality of the stream. You can visualise the effect by thinking of a video call freezing for a split second. Sure it's annoying, but your brain can easily fill in the gap. However, if you had a conversation with someone and their words were our of order, it'd be really confusing. The opposite is typically true for non real-time data, e.g. web traffic. It doesn't matter which image on the page loads first or last, as long as they all load within a few seconds. Phone networks try to maintain a QoS profile that's favourable for what you're sending. And sets up the underlying physical, logical and virtual channels a certain way if you're sending voice traffic. This includes configuring the underlying algorithms as well. Phone networks also favour low latency and reliable voice over everything else. It's what they're built for, sure it's nice to browse the web on your mobile, but reliability and coverage are more important for an operator. Coverage and quality do come into the equation due to the principles orthogonal signal's and data rates. But that's an entirely separate post. Ultimately, the QoS characteristics have alot to do with what radio technology is being utilised, congestion, signal strength etc. Some devices also do Deep Packet Inspection (DPI) where they read your messages, primarily DNS requests, to figure out things like if you're making a Skype call, or just browsing Reddit. The device can't see the contents of things that are encrypted, but it can almost always see the domains and sets up channels accordingly. Lots of operators don't use the DPI features, but they capability exists. However, it leads to a scenario where the network can easily tell if your making a voice call, but not necessarily one via the internet, e.g. Skype. And as the phone networks favour the stability of voice over everything else, they tend to use higher compression/quantisation algorithms for this type of traffic. The operators also want to preserve bandwidth for the sake of squeezing more people on the network, see my above point about orthogonal signal's. The result of the QoS profiles is that while voice transmissions can be easily understood, the data is smaller, but the quality doesn't sound quite as great. The importance to understand is that the traffic size has been reduced in favour of guaranteed fast delivery. The opposite is true if you're making a call via the internet, e.g Skype. It's the same microphone, but isn't able to set up the channel QoS characteristics accordingly as the encoding/decoding is handled by Skype, and not the operators network devices. Skype favours higher quality voice more than reliability, so uses higher quality encoding. It makes your microphone sound different depending whether you're making an actual voice call or a Skype call. However, if you're having connectivity problems with Skype. You almost certainly can still make a voice call as it's much more reliable. Source: - Telecommunications security researcher at Huawei for many years Edit: tried to make it easier to understand",
"The frequencies that are transferred over copper line are more narrow than the ear can hear. To keep phones backwards compatible with all existing phones, the frequencies in use are limited to the historical frequency range. This became apparent first with the invention of the 56k modem. It had a theoretical bandwidth of 56k, but an actual speed that was a bit less because the range of sound pitch isn’t big enough. Additionally, pushing sound over a copper wire affected different frequencies at different levels, like having a horrible equalizer built in. When FM radio and eventually CDs came out, they were a new technology that didn’t need to be transferred over phone lines, and could have a larger frequency range. With newer digital technologies, the sound frequencies that our ear can hear can be more accurately captured. It’s more accurate not to say that phones sound bad, but instead to say that everything else sounds better."
],
"score": [
11,
8
],
"text_urls": [
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|
[
"url"
] |
[
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|
gkpoew
|
How could people create detailed maps of continets hundred of years ago without being able to fly?
|
Technology
|
explainlikeimfive
|
{
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"They determined their position based on their speed, direction and at night with the stars. Hell of a job, but they got a lot of it done pretty well.",
"Set a datum - this is your 0,0,0 point. Then move to a point within sight of your datum. Take measurements from your datum to the new point. Record whatever is at your new point on your map, a hill, a crossroads, a stream, a church etc. Repeat until you have mapped the area.",
"Triangulation. Measure the distance between two points, then move around lining up triangles and doing the maths to work out the distances from the measured angles. This is how things are still mapped now. Aerial mapping isn’t as accurate.",
"They would either walk or sail alongside the coast and draw what they saw. Or for inland maps, I’d assume they would just free hand what they see as best as they could. Keep in mind that maps weren’t incredibly accurate back then."
],
"score": [
8,
6,
5,
4
],
"text_urls": [
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|
[
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] |
[
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|
gkrn0f
|
Why do TVs not equalise sound?
|
Whenever I have the volume set to a certain point, the ad break seems to be so loud. Why cant TVs just use an equaliser system? Or even simpler, base the volume on decibels, so if the volume is set at 16 dB, all sounds coming from the TV should stay at 16 dB. That would be better than setting only how loud the sound is regardless of decibels.
|
Technology
|
explainlikeimfive
|
{
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"fqsvact",
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"text": [
"It is done on purpose by the broadcasters. When an ad comes on most people go do something such as grab a drink. They boost the volume in hope you can still hear it in the other room.",
"You mean a compressor/limiter or an autogain and not a equalizer. Equalizer is for frequency response. Some ad companies like to make their ads as loud as possible to get peoples attention. There is actually a rule for broadcast tv that they cannot go over a certain standard which is the same most tv shows are mixed at. Im assuming your watching on a streaming service which isnt as regulated so you get a lot of ads being loud. There are a few reasons you dont see a method to auto regulate the volume built in to most tvs. Some tvs do have some means to do it, but most dont since they were made for broadcast tv where it isnt neccessary, but if your using something like a roku, firetv, ect this wouldnt be the case. Also compressors or limiters can affect the sound quality when the sound goes over their set threshold and autogain systems are either a bit slower or need to know the sound coming in before hand. The streaming devices or software could add these in but the advertisers dont want it amd they want to keep their advertisers happy because thats thier major source of income and there isnt any regulatory body for the different streaming services that can step in and force them to."
],
"score": [
8,
3
],
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|
[
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gkt931
|
With the invention of guns, why did armor get so much more lightweight
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqt49yj",
"fqta79n"
],
"text": [
"You can't effectively encase a person in bulletproof armor. If you do that, the person becomes pretty immobile since the armor would be so heavy and bulky. (Imagine a bomb disposal suit) Instead you protect the most important bits (heart and head), and leave the rest. With modern medicine the person still has a pretty good chance if hit elsewhere on the body. This ensures the soldier remains mobile since being able to run and duck into cover is better for survivability than being bulletproof.",
"The heavy armor wasn't stopping the bullets enough. Armor cost money, is more tiring to wear then a shirt, and slows you down. So rather than have an expensive, slow, and tired soldier running around and dying to gun shots. You could get a cheap, fast, and fresh soldier running around and dying to gun shots less than the armor guy. Once technology caught up and started making armor that would protect from a bullet with a reasonable weight, it came back."
],
"score": [
9,
3
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[
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|
gkupku
|
Why are computer CPUs the size they are? Wouldn't making them bigger give way to more processing power without needing better technology?
|
Technology
|
explainlikeimfive
|
{
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"Although electricity moves *very* fast (almost the speed of light) it still has to travel, and traveling takes time. Modern processors are cycling more than 3,000,000,000 times every second per core. Even a tiny tiny fraction of a second extra per cycle adds up. So, you want to pack everything as close together as possible. Just making the processor smaller with the same number of transistors makes it go faster because the electricity has less distance to travel. That also makes it more efficient, since every bit of metal and semiconductor has some electrical resistance. If you have less metal for the electricity to pass through, it takes less power to run the CPU. But that creates the problem that you're also packing all of the heat closer together, too. Every little bit of metal or semiconductor is generating heat with every cycle, and when you pack them close together it's like putting a bunch of space heaters in a room together. More heat means a bigger, more powerful heat sink. When the components are too close together they also start \"leaking\" electrical signals between them, causing false signals which have to be re-checked, which of course slows down the computer. So without new technology they can't be packed much closer together than they are. So why not just build bigger chips with the same sized components, but more of them? Partly because of cost. More powerful CPUs will always be more expensive, and there's a point when 90% of users don't need anything that powerful and won't be willing to spend the money on it. There *are* CPUs that are just larger, but they're normally for special uses like servers. Those chips need special motherboards, which is another problem. Most motherboards for your average user have some backwards compatibility. CPUs are made to fit within the same socket as past generations, so your average user can upgrade to a better CPU without having to throw out half their computer. Even different normal CPU sockets are *around* the same size so when you're designing a motherboard you know how big the socket should be. Server CPUs also often need special RAM and more powerful power supplies, too. At some point it's just not worth it to manufacture a larger CPU when few people are going to buy it. Or else, manufacture them but design them for completely different, niche uses and price them accordingly. Physically larger CPUs also mean yet more heat. More components make even more heat, and it still has to go somewhere. Bigger, stronger heat sinks get expensive so, again, it becomes more than most users will spend or want to deal with. That may change as the market evolves, but given that 90% of users aren't doing anything more computationally stressful than word processing and internet browsing...probably not soon. TL;DR: Like shorter roads, smaller distances between components makes the CPU go faster. Physics problems like quantum tunneling and waste heat from electrical resistance limit how small components be and how close together they are. Economics limits what people are willing to pay for so just making CPUs with more components is not generally worth it for manufacturers. Current generations of processors are right about in the sweet spot of being as small as the CPU can physically be + having the most components (and therefore processing power) that people are willing to pay for. (And there is a wide range of CPU types, sizes, and costs for people to choose from.) EDIT: Other comments below have pointed out the manufacturing process is cheaper with smaller wafers because the odds of having a fatal flaw increase as the wafer size increases. That's not something I was aware of! So those comments are totally worth reading (and upvoting). EDIT2: Yes, Intel tends not to be backwards compatible and also sucks. This edit brought to you by the AMD Gang.",
"No. In fact, making a CPU smaller makes it faster. CPUs are already bumping against the speed of light limit (seriously), and limited in part by how fast signals can travel from one end to the other. The other issue is that CPU manufacturing has a probability of having a defect in it. The bigger the CPU, the bigger the chance that a defect will be found inside it, and it'll need to be thrown out. [See the picture]( URL_0 ). So making a CPU smaller makes it cheaper, because each defective CPU still costs money to make, and the cost of those has to be accounted for in the price of the CPU.",
"The explanations posted are good, but I love this question because the actual math is so easy to understand. Start with how big a processor is, which is **like an inch or two across** right? Then think about how fast they're doing stuff. The fastest boast a \"4.0 GHz\" (Gigahertz), which is the number of operations they can do in a second. That's **4 billion operations per second**. But then how long does it take them to do a single operation? Quick conversion, it's **200 picoseconds**. Then, we know the speed of light right? c is about **300,000 km/s**. So the question is, how far can light, the fastest thing around, travel in 200 picoseconds? It turns out, when you crunch all the numbers, the answer is **2.4 inches**. Once you remember that it's not moving straight it's gotta wind around in there, it's easy to see why a processor can't possibly be bigger than an inch or two across and still run that fast!",
"Things in a CPU happen extremely quickly. The smaller/closer together things are, the more efficient they can be.",
"For the purpose of a CPU, the signals that matter are 1s and 0s - electric blips or no-blips. But as long as the 1s and 0s are received and processed, it doesn't matter if they are \"big\" or \"small\", or carried down large hallways or small corridors. Let's say you are carrying boxes that either contain a signal or are empty. On old computers, huge boxes were carried by dumptrucks running down big roads - noisy, inefficient and large. On new computers, small boxes are carried by small scooters down narrow tunnels. Physically much smaller, requires much less power. But this is great, since the only thing that matters is whether there is a signal in a box or not. You want the pathways and boxes to be as small as possible, as long as they are still received and registered correctly. What I'm talking about here is really the die shrink process: [ URL_0 ]( URL_3 ) whereby a certain process is just shrunk down in size. This is always a good thing. A huge part of making computers smaller, cooler and faster and being able to be in phones is this shrinking processor. Another question is making the processors have a bigger volume - at the same time as they shrink internally. Smaller pathways for the signals, just more of them. That's a more tricky one. It's partly that there's no need to, because the actions of a CPU core, the \"instruction set\" so to speak, can be performed with a given layout, big or small - so adding more volume to a CPU core has no reason. Instead, as you shrink down the pathways for each core, you add more cores, letting you run more programs at the same time. CPUs have hence already been made \"much bigger\" than they used to be, in the sense that they have more cores - if they had as few cores as before, with the pathway shrinkage, they would be even tinier. You can also add things to processor cores, like a form of fast memory (cache) making them run faster, but there's a limit to how well the improvement scales. Let's say that for a CPU to function as a CPU, and perform its instruction set: [ URL_2 ]( URL_1 ) it needs to contain a spoon, a fork and a knife, regardless of their sizes. When people write programs, they do so presuming that these are the only tools in the CPU. You get great gains from shrinking the tools inside, but there's no reason to add more utensils. However, as you shrink them, you get the space to add multiple CPU cores each containing a spoon, a fork and a knife.",
"The opposite is true. Think about factories you want to connect with roads. The longer the roads, the longer it takes you to travel them. So to make things (data in a CPU) go from one factory to the other, you want the roads as short as possible. But, if those factories are too close together, pollution (heat in a CPU) becomes a problem. So the only way to have those factories closer together is by making them produce less pollution (heat). Therefore there is the balance to cram everything on a CPU as close together as possible, but not so close that it overheats.",
"Bigger CPUs have more chances for stuff to go wrong in the manufacturing process. Plus, they're already plenty big, compared to the transistors on them. Computers with more than one CPU do exist, if you want a \"bigger CPU\"",
"Yes, you could do that, and there are companies making chips the size of dinner plates. The problem is it is very very expensive. To make a CPU you start with a piece of silicone about the size of a dinner plate and \"print\" your chip design on it as many times as it fits. So if you can put 1000 CPUs on your plate sized silicone now 1000 people pay for that batch rather than one person paying for the whole plate sized silicone. *Slightly more technical details...A bigger chip is great for paralle computing or lots of cores (running lots of things together) but not every application/chip would benifit from scaling like that. But even for basic Nvidia chips, the faster one have a bigger die size (chip size).",
"Check out this video by the great Grace Hopper: URL_0 The speed of light sounds really really fast, until you're dealing with the order of nanoseconds and microseconds. I'm sure everyone is familiar with GHz (gigahertz) and such being a very rough measure of processor speed. Consider a simple 3 GHz processor. This means that for every nanosecond, this processor flips a switch (called a \"clock) exactly 3 times. The clock is used for synchronizing the entire processor and is almost a hard requirement (some clockless/asynchronous designs exist, but they are very complex) in modern processor design. Consider If you build a large processor where the middle of the processor is the clock, memory is on one side, and the circuitry for adding two numbers is on the opposite side as memory. The memory and addition circuit are each 10cm away from the clock. With a design like this, if you had some addition operation that you wanted to then put into memory, and the processor frequency is 3GHz, then as soon as the addition circuit received the clock signal, the clock signal would change at the source. To put this into distance: * clock to addition: 10cm/1 clock cycle * addition operation: typically 1 clock cycle * addition to memory: 20cm/2 clock cycles Basically bigger distance means more propagation delay which means much more complexity with keeping the clock rate of a processor high while not running into problems with components of the processor falling out of sync with the clock, or not being able to \"stabilize\" on a result within the designated clock cycle. Smaller processor size means that you can push the \"wiring\" of a processor faster, even if the actual components (ie, transistors) are still effectively fixed speed. For one more example, consider some circuit that adds numbers. It is 10cm in area. This means that when you feed data into one side, assuming perfect component behavior etc, that the result comes out the other side in at least 0.33 nanoseconds or more typically much more time. Now, you invent something and shrink the design of this component to fit into 1cm. Now the result comes back after just 0.033 nanoseconds. The reduction in propagation delay almost always gives a huge advantage, even with a reduction in the quality of smaller transistors that might cause more \"stability delay\"",
"We do do this. Well, sort of. I work for a big hosting company. There's both core count and speed, more cores makes for a bigger physical processor, more speed makes each core faster but heat up more, so whether you are upping the clock or adding more cores the whole proc is generating more heat. There's a limit to having that much heat in a single space before things like melting (have seen this) happen. Usually what we do to pack more processing in a box is to get motherboards that can support multiple CPUs, dual socket is common and quad socket is somewhat, believe you can get 8 sockets even, each socket can support over a TB of memory too so they get pretty big. The problem is those mobos are expensive, the more you ramp a single system up the more exponentially the price rises. So what we've done server side is write our code in ways it can be split up and served across multiple servers instead of multiple cores, since they both take more work than a program that runs on a single core anyway. As to why they don't simply increase performance per core, takes a whole lot of engineering to make that happen, and either way you still deal with heat. It's more practical to scale horizontally than vertically these days.",
"Cost. To build a computer chip you start with a circular flat piece of metal called a wafer. The wafer is a fixed cost, say $1000, and a fixed size, say 12\" diameter. Therefore, the cost of the chip is directly related to the size. If you can fit 10 chips on your wafer, then your chips would cost $100 each to make. But if you fit 100 chips on your wafer, then your chips would cost $10 each to make.",
"Not posting this comment to diminish what /u/RhynoD or others have already said, what they said is absolutely true. CPU manufacturers want them to be small, but not too small. However, not all CPUs are the same size, and many higher-end CPUs are physically larger. In fact, the actual chip in consumer CPUs vary in size, even though the total size of the CPU does not. What you see the CPU is a bit of the printed circuit board (the little green board that contains all the connections between the chip and the rest of the computer) and the heat spreader on top. As the name implies, the heat spreader takes the heat generated by the CPU chip and spreads it out to improve cooling. Under the heatspreader is the CPU chip itself. Even though the board and the heatspreader size doesn't change, the chip underneath can vary. For example, [here is a size comparison between three different Intel CPUs]( URL_0 ). The board and heatspreader remain the same size between all three CPUs. AMD and Intel have both decided on similar (although not the same) size CPU board/heatsink size just so both their low end and their high end CPUs of a generation can all work on the same motherboards and other products like heatsinks. Their professional level CPUs, such as some of Intel Xeon or AMD's Threadripper/EPYC CPUS have physically larger heat spreader/boards in addition to having massive chips. Part of the reason certain Xeon chips cost over ten thousand dollars is that large single-chip CPUs have high failure rates per /u/dale_glass comment, so they need to charge the price for a black market kidney to make their money back. AMD's high end CPUs these days are actually a bunch of smaller CPU \"chiplets\" acting as a single CPU, which allows them pack a ton of CPU horsepower in a package you will only need to sell half of your kidney for.",
"The speed of light itself makes larger form factor CPUs _slower_ than what we have because of distance travelled. Furthermore, have you noticed that CPU speeds have not changed much in 10 years or so? That pesky speed of light thing again. We can only get so many cycles of ones and zeroes packed in. Don't get me wrong modern CPUs are better in other regards, but until we can break the laws of physics it's a game of efficiency and multi threading, not of speed. In theory quantum entanglement could break that barrier, but so could harvesting unicorn semen. Quantum research and related disciplines have taught us alot, but it's still all based around the possibility that we may one day figure out how to entangle particles for instant transmission of state... something we cannot do and aren't even sure is actually possible. Theorizing about what could be done if we did mange this does advance science better than theorizing about the fastest way to bring unicorns to orgasm, but the likelihood of achieving either of these things is pretty much exactly the same."
],
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11988,
508,
102,
46,
20,
18,
12,
9,
8,
7,
5,
5,
3
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"text_urls": [
[],
[
"https://slideplayer.com/slide/5218297/16/images/3/Effect+of+Die+Size+on+Yield.jpg"
],
[],
[],
[
"https://en.wikipedia.org/wiki/Die\\_shrink",
"https://en.wikipedia.org/wiki/Comparison_of_instruction_set_architectures",
"https://en.wikipedia.org/wiki/Comparison\\_of\\_instruction\\_set\\_architectures",
"https://en.wikipedia.org/wiki/Die_shrink"
],
[],
[],
[],
[
"https://www.youtube.com/watch?v=9eyFDBPk4Yw"
],
[],
[],
[
"https://images.anandtech.com/doci/13400/9900K%20Mockup.jpg"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gkwj47
|
How do cassette tapes work? The tape looks blank so how does the cassette player read the tape?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqttb6k"
],
"text": [
"Hi :-) > blank While you can buy something like the \"3M Magnetic Tape Viewer\" (A disc you can place on tape to show the weak magnetic fields), you can easily try this at home: - Take an old/expired card with a magnet strip (e.g. gift-card). - Use some iron powder (Nail, file) and sprinkle it on top of the magnet strip. Gently tap it. - You can see a \"barcode\" where the strip is magnetized. Tapes have a similar structure (plastic tape, coated with something containing iron particles). As you can't see which way the tiny tiny iron particles point in the coating, it always looks the same with your eye. > work Audio is just vibrations in the air. A microphone pics these up and turns it into electronic signals, either analog as varying voltage, or digital as a lot of on/off signals per second. There's a magnetic head in the tape player that can re-arrange the iron particles according to the signal the microphone picked up. The faster the tape moves while stuff is recorded, the better the quality. Thus you could sometimes find dictaphones with two settings (same with videotapes). > read And the head in a player can read the weak magnetic field, runs that signal through an amplifier, turning the recording back into something that can be played through a speaker."
],
"score": [
14
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gkx163
|
How are Integrated Circuit Chips programmable?
|
How are some integrated chips programmable? I understand that most IC chips are not, they are designed to do one function, and they will do that particular function when integrated within a larger system. However, some other IC chips are programmable. For example, a software programmer can write a completely new program and have an IC chip (probably the SoC/processor) implement it. This means that the IC chip is doing something completely new and not contemplated when originally designed/manufactured. In order for it to carry out the new function (program), does it not need a new pattern of connections between the transistors? But that would entail physical change in the chip, as I see it. So... how is it that you can write a completely new program and have that program's logic be implemented on an IC chip? Thanks!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqtty8o"
],
"text": [
"I think what you're talking about is FPGAs (Field Programmable Gate Arrays). Back in the old days you had PLA (Programmable Logc Array Logic), the chips had loads of logic gates on them like AND, OR, NAND, NOR etc. These are the logic devices that make up a computer as we know it. Think about how you add a single bit. If both bits have a 1 you know you need the sum to be a 0 etc this produces a truth table like this (basically listing all inputs and their respective outputs): URL_0 Well a PLAs had loads of gates like this: URL_1 You'd basically burn the connect you would or implement in ROM. FPGAs take this further and instead of having the gates have LUTs (Look Up Tables) that you can program to behave like gates. A LUT is basically a truth table you have programmed so you can have a LUT that does an OR operation. The FPGAs manufacturers also saw that people were using FPGAs for DSP (Digital Signal Processing) like creating filters to remove high frequencies from a signal -- a high pass filter. These DSP blocks were then added to the IC to speed them up. The ingenious thing about FPGAs is the field programmable part. You program then in a HDL (Hardware Description Language) the main ones are Verilog and HDL. If you have every used C Verilog will look very similar to you but don't get confused they are **not** the same. You are describing hardware, not telling the hardware what to do. When you compile your HDL you turn it into a netlist (what gates you use, what clocks you use etc), then there's place and route (how you connect everything together onto a die). Complex designs can take **days** on a powerful computer, that's why 90% of your time is spent verifying designs. And I'm not joking companies such as Arm, Intel and AMD have positions just for testing. The final design is then put into a device specific format and into memory that the device reads on boot-up. Source: MEng in Electronic Engineering EDIT: May have forgotten something I do software now hahaha"
],
"score": [
7
],
"text_urls": [
[
"https://i.stack.imgur.com/jUkIo.jpg",
"https://en.wikipedia.org/wiki/File:Programmable_logic_array_(schematic_drawing_example).svg"
]
]
}
|
[
"url"
] |
[
"url"
] |
gkxuzn
|
Why does taking a photo of a screen cause lines to appear? Why do these lines change as I zoom in on the picture?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqtyn1e"
],
"text": [
"They're called Moiré patterns URL_0 It's caued by the interferance pattern between the pixel grid in your camera's sensor, the pixel grid on the screen your photographing and the pixel grid on your phone's screen (which is why they change when you zoom) If you take a picture of window screen or other regular square pattern you can see the same thing. You can even see them in the real world by looking through two layers of wire screens (an apropriate distance appart) (The reason they're curved is because different parts of the monitor are different distances from the camera sensor so the interferance frequency changes .)"
],
"score": [
197
],
"text_urls": [
[
"http://en.wikipedia.org/wiki/Moir%C3%A9_pattern"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
gkznqu
|
How is electricity/energy from things like solar panels or generators stored? If the answer is batteries, how do batteries work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqua53i"
],
"text": [
"The answer *is* batteries for small applications, like a solar-powered radio or your car with an alternator. Not the case for large-scale like nationwide electric grids, the batteries become too big and too expensive too quickly. For this there are alternatives like using excess energy to pump water uphill and let it flow back down over a generator when energy production is down, or compressing air in a cavern (though air compression is pretty dang lossy) is also being tinkered with. Some solar sites have a big tower in the middle that gets sunlight reflected onto it so it is filled with molten salt, it will retain that heat after sundown to be used to make some more power. But typically on the national scale, it *isn't* stored, with solar being an exception here and there, because power plants can usually rise to meet demand at least to their limit. Let's say we have a coal-fired generator where the generator itself spins 60 times a second to make the 60-Hz power we use in America, and can make 10MW of power cut the demand on it right now is 5MW. Some giant factory turns on and now power demand increases by 1MW and power demand shows up as increased resistance (harder to turn) at the generator so it would slow to 50RPM. So shovel more coal in or turn up the steam and get it back to 60. Exactly the same as giving a car more gas when going uphill."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gl031d
|
what is the difference between a laser and a regular flashlight?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqubbhl",
"fquc621"
],
"text": [
"A laser is monochromatic, basically a single wavelength of light. It is also typically *coherent*, meaning it stays in lockstep with itself, and does not tend to diverge, or spread out over fairly long distances. So the energy doesn't spread out, and the spot produced is extremely bright. A flashlight, whether incandescent or LED, emits a pretty broad spectrum of light, and the emission of that light is random, and without very good mirrors and lenses, begins to spread out immediately, producing a broad, dimmer pattern.",
"Flashlites have a lamp inside them. Regular lamps generate light in many ever so slightly different colors at the same time. The light is leaving the flashlite at random times and to all directions. The light waves are also oriented differently and the whole situation is messy. This creates the spread of light in all directions. Lasers don't have lamps. They work by exciting electrons to a higher state. The electrons naturally return to the regular state and release light. This light is released at perfectly regular intervals, all of the waves are oriented the same way and travel exactly to the same direction. This results in a clean beam of laser light."
],
"score": [
7,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gl1kem
|
Why do most games only use a single core when multi core processors have been standard for more than a decade now?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqumt4t",
"fqum4kp",
"fqukwpj",
"fqv3hn0",
"fquss1j"
],
"text": [
"Most newer games are multithreaded. That being said, I can say from personal experience from programming multithreaded applications that the level of complexity from single threaded to multithreaded is exponential. Trying to get threads to cooperate with each other is a nightmare and requires careful planning. The best ways to get multithreading to work involves setting up programming in such a way that you can divide the work while limiting the communications needed between each job. It's not easy.",
"Most games actually do use multiple cores for things like audio or queueing mechanisms. However, the main game logic all requires access to the game state. If you start manipulating the game state in multiple threads, you run the risk of having things happen out of sequence. For instance, if two objects were moving into each other, and they were on separate threads, getting all the coordinates of the other, you might not necessarily get the X, Y, and Z for the same instant. The object could be moving, and between your calls for X and Y, Z changed. Making this thread-safe means that you have to block these calls if they're in the process of being updated, and block the updates if they're in the process of being retrieved. It's an easy thing to do for asynchronous programs like web servers, but in a game, creates a very unresponsive experience.",
"It's easier to program. That said, modern games don't use a single core anymore. This might have worked with dual core CPUs, but with 8 and 16 core CPUs being available, discarding 90% of a CPUs capability is just not a good idea. An exception can be made for indie games that are low tech enough that multicore CPU is just not needed.",
"Games are a really annoying type of software when it comes to taking advantage of multiple threads. Lets start at the other end. In an ideal case the thing your program is trying to do naturally splits in equal sub-problems. Want to convert lots of images? Just give each thread its own set of images. The threads don't have to interact and can just churn away independently. Want to multiply two big matrices? Thanks to how the math works out you can split a big matrix multiply into equally sized smaller ones and just combine the result later. On the other end you have heterogeneous problems like a game. You do a bunch of very different things like rendering images, processing user input, processing network communication, update game logic, update physics etc. Naively you can just put every one of these in their own thread (still tricky because they interact of course). That way you get **concurrency**, meaning stuff gets processed at the same time. But not necessarily **parallel efficiency** or performance. Chances are one of those things takes longer than the others. So most of the threads/cores will just do their small task and then wait around for the big one to finish. For example I could have my code use four cores/threads by having one send drawing commands to the GPU (semi expensive), have one process input (extremely cheap), one for network (also cheap), one for physics (very expensive). I'm \"using\" 4 cores but if you were to look at the task manager only the one doing the physics would show a high utilization. So you have to find a way to split this diverse set of tasks into equally expensive chunks. Which is a hard problem by itself and usually complicated by not everything being easy to split into independent sub problems. To make things even worse, you don't just have a large pile of work that you can churn away and have the utilization even out over enough time. You have to present a frame after ever 16ms (60FPS) on the clock. So that's like having a large team of people work on a project but your manager is having \"synchronization meetings\" every 15 minutes. Which is very disruptive for everyone's productivity. If one person takes a bathroom break in one of those intervals then everything gets thrown off because now everyone who depended on that person is \"late\" on their 15min chunk of work.",
"When you program for a single core you know the exact order that instructions will execute in. When you do that on more than one core you know the order of instructions on any particular core but you don’t know how they’ll relate to each other. So if one core executes AB and an other does CD the total order could be ABCD, CDAB, ACBD, or any other combination that puts A before B and C before D. Often one instruction depends on the output of an instruction on an other core. Coordinating them is where the difficulty shows up."
],
"score": [
45,
20,
10,
8,
4
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gl79p3
|
How do spacecraft navigate through and avoid collision with the asteroids in the asteroid belt?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqvoes2",
"fqvpc4t"
],
"text": [
"Asteroid belts aren't like they're depicted in movies. At least ours isn't. The average gap between asteroids in our belt is 600,000 miles, so it wouldn't be hard to slip between them",
"The asteroid belt is not very densely populated, it’s more a graveyard orbit for material that gets kept out of the inner solar system by Jupiter’s gravity. Unlike in many popular films the average distance between objects in the asteroid belt is nearly 1 million kilometers. To answer your question: The density of the asteroid belt is so low that NASA does not even consider it as a factor when plotting courses for space flights."
],
"score": [
37,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gl81mg
|
How do they make a Blu-ray or 4K version of a movie that was filmed before those technologies existed?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqvunub",
"fqvtgeo"
],
"text": [
"The 35mm film was the standard way to recode mainstream moves from the 1910s until you start to use digital cameras. Digital cameras start to be used in mainstream moves around the year 2000. Digital becomes dominant in the mid 2010s when you 4K cameras. 35mm film do not have a resolution like a digital camera but a high-quality film in the good light condition is around the resolution of a 6K video. So you can scan them and get a 4K video because the \"resolution\" of the film is higher. It is moving from 2000s with captured with lower resolution digital camera that is are to make 4K not a high-quality move production at least as far back as the 1930s. Lots of TV was also recorded in 35mm film and can be converted but from 1980 some tv was recorded on videotapes and before that some on 16mm film that had a lot of lower quality.",
"Movie film is insanely high definition. Way higher than any currently affordable at-home media. So if the 4K release is made from a decent copy of the original film it is likely true 4k quality."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
glbz33
|
how can a mobile phone transmit high data rates from a tiny omni directional antenna with low power and no line of sight over many kilometers?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqwi19y"
],
"text": [
"Your phone cheats - it only has to send to the nearest cell tower where wires then continue the signal over to the tower where the info needs to be delivered. The signal clarity is from the brilliance of digital communications. The most common form is phase modulation. Radio has amplitude modulation (AM) and frequency modulation (FM) but phase modulation (technically phase keying) is superior in terms of clarity and power but only works with digital systems unlike analog radio."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
glf3ax
|
Why do wires get tangled up in so weird,crazy ways around everything?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqwz2fj",
"fqwy80d"
],
"text": [
"It has to do with the length of the cord and the ‘agitation rate. I remember a year or two ago reading about actual research done by Apple in how their earbuds get so tangled. I believe a wire only needs to cross over 2-3 times over another part of the cord for chaos theory sets in and you get a random intestine like mess Edit: I found the [SITE]( URL_0 ) that links the study. It is interesting math nerd stuff actually.",
"Because over time things get less ordered. Any shape of the wires which is not tangled has more order than a shape where it is tangled, so over time more tangles appear. Google \"entropy\" if you want a more technical explanation"
],
"score": [
7,
3
],
"text_urls": [
[
"https://www.sciencealert.com/the-mathematical-law-that-causes-your-headphones-to-tangle"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
glic8d
|
Why have we not fully explored the Pyramids of Giza? And how have so much of them remained untouched/unexplored throughout history?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqxjp9w"
],
"text": [
"People *have* been inside, but only into relatively accessible chambers. The pyramids are protected by Egyptian law, and it is nearly impossible to receive a permit to do anything that may alter them, like dismantling them or drilling holes to see what's on the other side of walls."
],
"score": [
12
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gllr5u
|
difference between making a 2D and 3D game
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqy92kg"
],
"text": [
"3D is more difficult, by a huge margin. The why is pretty boring: it's basically because the math is much more complicated when working in 3D (2D allow a bunch of simplifications that you can not do in 3D) One example of something that is simple in 2D but a nightmare in 3D is rotation. When working in a plan you only have one possible axis of rotation. In space there are infinitely many of them..."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
glmh08
|
What is the filtration system for tap water like and should I trust it as drinking water?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqyf0lz"
],
"text": [
"The good people of Flint, MI would say no. I have one of those on-the-faucet filters and it works great. Makes the water taste better, too. They're pretty cheap and the replacement filters aren't expensive."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
glnr4z
|
How did early sailors like [Vasco da Gama] know were they were when sailing?
|
**In Detail please** Also mentioning the tools, instruments and the process they used will be helpful, Thanks!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqypa8t",
"fqyulws"
],
"text": [
"The sun during the day, the stars at night and pointing confidently in a direction when it was cloudy.",
"The tool = sextant The process = sail south to the correct latitude and then west until you reach land The 2D process, called the longitude problem back then, wasn't solved until the 1760s. You need a sextant and a good clock."
],
"score": [
10,
9
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
glo5aj
|
When we mute our phones, do the apps actually stop sending the data to generate sound at the speakers?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqyuzfk",
"fqz3ufx",
"fqyujgl",
"fqzf0of",
"fqza3un"
],
"text": [
"Since Android has system-level volume control, changing volume in Android seamlessly changes the volume so other apps don't have to worry about it. So if you mute using the Android UI, the apps are still running as normal, but the audio passes through a system-level mixer before being played over the speaker. Muting is really just a toggle for zero volume that remembers the last volume you had it at. Short answer is yes the apps send audio data (unless they have options to customize volume or muting, etc), but the OS controls overall volume. An app could be written to check to see if it's muted and if so avoid processing sound, as long as the OS underneath provides access to volume information.",
"There's still data moving, but audio is one of the least taxing things you will ever ask a computer to do. 44KHz, 16-bit sound? 88Kb/s per channel, 176Kb/s for stereo. It's pathetic. The processor can do that in idle and barely bother waking up, because it just shoves it into a buffer and processes it all in a fraction of a second. Audio is mainly \"waiting for the speaker to be ready for the next byte\", and it's incredibly slow by modern computing standards. There's still thousands of data streams being processed by a phone all the time, but they don't result in anything and can be done in fractions of a second and then put back to sleep. Hell, if nothing else, it has to listen out for text messages, Internet data, phone calls, Bluetooth devices that you usually join to it, button presses, swipes, fingerprint activation, etc. Some are catered for by specialist chips but those chips are doing just the same - waiting for the data stream to indicate that something needs to be done, and then \"interrupting\" the main CPU to get it to do something with the data. Somewhere in any modern machine there are probably dozens of audio channels playing away to themselves (even if they're just sending 0 constantly), they're mixed and send to a variety of destinations (speakers, headphone, Bluetooth, the apps themselves to send up to Facebook or whatever). Your Windows machine has a channel for each program running, in effect, so you can make your browser quieter than your movie without having to adjust the central system volume, and so on. But if the volume is down, or off, or the device missing then the stream just gets mixed and then... nothing happens to it. It might be that the speaker is just sent zeroes, or that it's actual power is disconnected (depending on the type of speaker), but it makes no real difference in terms of power anyway. A headphone cable is probably only 1V peak-to-peak at it's loudest, and an internal speaker isn't far off, and a Bluetooth speaker is separately powered and it's the radio signal to it that costs power. But no different to the stream off data coming off your touchscreen even though you're not actually pressing anything - it gets sent, filtered (so specks of dirt aren't mistaken for fingers), processed, converted to a suitable format, and sent on their way. It's probably only \"off\" when the phone is locked, but even then it has to wake up instantly so likely it's only in a low-power mode rather than actually off. So many bytes flowing through your phone even on idle for a few minutes that you wouldn't be able to process them all as a human in a year, most likely. But computers are built for that, and an audio stream is one of the simplest and smallest lots of data of all. Your USB hub (even an internal one like on a phone or laptop) with nothing plugged in communicates hundreds of times faster, using more power, all the time the machine is on.",
"It's easier for the phone manufacturer to control volume and have the apps just play an audio signal rather than having apps also controlling phone performance It's impossible to say for certain as there are too many apps to account but typically the apps just play music independent of phone volume.",
"If you mute it in the app, my apps stop playing the sound file. If you mute it in the OS, it still plays the sound, but it doesn't make it to the speaker.",
"The amp that powers the speakers is being told by the phone to not output any power when it's muted, that's it. So yes, the sound data is still being processed, it just isn't being output since the amp is being told there is no energy (Zero volume). If you want no audio processing, you would have to disable the drivers. That would theoretically free up resources as it would not be transferring sound data at all even if you made the amp output max power (Full volume)"
],
"score": [
508,
109,
10,
5,
5
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gloivt
|
Can someone explain the latency we experience with bluetooth headphones although radio waves travel faster than electrons/electricity?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqytajp"
],
"text": [
"Simply put, bluetooth is a short range, low power, wireless network. Each device in the network contains a small, cheap processor that handles the conversion to and from digital wireless to analog audio. This conversion, because of relatively low-end processors, adds roughly 200ms or so from transmission to reception. This has something to do with the codecs being used (software), but it's also just inherent in the design. In some cases this can be made worse by poor tech (Android had issues) More modern standards minimize this, but all your devices have to support it."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
glqkuw
|
How do some websites trap you in an endless cycle of reloading the page when you try to escape with the back button?
|
This is so frustrating! Thanks!!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqz6sy8",
"fqz878m"
],
"text": [
"The previous page was an automatic redirect. Each time you go back to that page it tries to redirect you. Click the back button twice quickly to get past the redirect page :)",
"You land on page A. Page A has code that says: \"Immediately go to Page B.\" So you ultimately end up on Page B. When you hit the back button, it takes you to Page A."
],
"score": [
6,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gls2hk
|
What exactly is a transistor, and how do they work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fqzfr0s"
],
"text": [
"A transistor is an electronic gate(most of the time, a few other fields like microfluidics also uses them). The most basic version has 2 inputs and 1 output. 1 input will control wether things can travel through (gate) and the other input (the source) could be thought of as what would go through. For semiconductor transistors (the type in basically all electronics) they use how semiconductors conduct in order to make a really thin wire that lets stuff through normally but will stop lettting stuff through when an electric field is going through it. The gate mentioned before is a wire placed really close to the thin wire and when it's turned on it produces an electric field which stops the thin wire from letting anything through. If you want me to go for an eli18 let me know."
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
glwyzz
|
How do C-RAM systems work? (Counter rocket, artillery, and mortar)
|
Title
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr0b3l1"
],
"text": [
"Think of the C-RAM system as a really big gun that can shoot a lot of big bullets at an extremely high rate of fire. Now, attach a computer, a radar, and an infrared camera to the big gun and point it towards an area where you're expecting indirect fire munitions to be coming from. Once the computer detects an object within its radar's proximity, it asks itself three questions: 1. Is it coming towards me or going away from me? If it's going away from me, it's probably not my business. If it's coming towards me, go to step 2. 2. Is the object's trajectory going to hit me or near me? If not, leave it alone. If it's going to hit me or hit close to me, go to step 3. 3. Is the object going above a certain minimum speed and/or below a certain maximum speed? If it's too slow, it's probably not a rocket, artillery, or mortar round, and so I won't fire. If it's too fast, it's beyond my capabilities to actually track it, and so I won't fire. But if it's fast enough to be indirect fire munition and slow enough for me to track, then I will begin firing at the object. Once the object is now longer moving within the radar's range, the C-RAM will go to the next target. For clarity, C-RAMs are land-based big guns that are copies of the big guns they put on warships, which are called CIWS (Close-In Weapons Systems). C-RAMS fire big solid bullets made of tungsten to hopefully penetrate the incoming projectile and cause it detonate before reaching its target. The CIWS big guns that are installed on ships shoot high-explosive bullets that explode in midair right before reaching their target to attempt the damage or destroy the incoming projectiles with shrapnel before they reach their target. Some defense contractors are also fielding laser-based C-RAMS that track incoming projectiles and focus a high-energy laser beam on them to detonate/destroy them in midair, as opposed to shooting bullets at the incoming projectile."
],
"score": [
16
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
glz20o
|
how can blockchain prevent election rigging while making sure only eligible people get to cast their ballot?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr0ui28",
"fr12596"
],
"text": [
"Blockchain is, when you get to the bottom of it, just a read-only memory. It allows you to write something that everyone can read but no one can edit later. I'm sure that can play a part within some greater election-improving system. But if someone simply says \"We will solve it with blockchain\", he's just dropping buzzwords.",
"Short answer is that it can't. Longer answer is that, under the right circumstances blockchain could help prevent certain kinds of fraud. In states where voter ID verification is required, voters could be entered into the blockchain ledger when they vote. This would largely prevent that vote from being changed as well as eliminate any ambiguity in that vote. Would also eliminate errors in tallying. Problem is that this changing votes probably isn't a common enough thing to go to this effort to prevent. Ambiguity is definitely a problem, but not one that needs blockchain to address. Same with tallying errors. Problem is that blockchain won't help with common voting problems. It's a complicated solution to an edge-case problem."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gm07ek
|
How does microphone feedback work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr0qfaj"
],
"text": [
"A bit of sound enters the mic, plays out the speaker which is then picked up by the mic. Oh course the speaker will play that again like an echo almost but feedback does this thousands of times a second-playing the sound and picking back up, repeat. I cannot explain for certain why the tone climbs to a higher pitch; but I have, for fun, held a mic up to a speaker when it's really quiet and still seems to happen when close enough."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gm0r60
|
Why is red light used for night vision? Why not yellow or other colours of light?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr0tqaz"
],
"text": [
"Red light is used to help prevent loss of night vision because there are less red receptors in the human eye. Only the red receptors lose their sensitivity, leaving the green and blue receptors unaffected and retaining their dark sensitivity. However, it has since been found that the levels of light affect night vision more than colour. That's why aircraft cockpits don't use red light in the dark as it makes little difference in practice. Night vision takes about 10 minutes to develop and the best way of keeping it working is to cover one eye while working in light, uncovering it when back in the dark again."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gm0zvz
|
Is it possible to track a mobile phone location just from a phone call, without GPS?
|
If yes how? If no, why not?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr0v19z"
],
"text": [
"If you're the police and want to know the location of a mobile phone, you can just call the network operator. They know which of their towers had the strongest signal and therefore probably was closest to the phone. That gives you at least a rough location. I've heard that nowadays they can narrow it down further by correlating the signal strengths of various towers in the vicinity. The accuracy of this is probably still limited compared to the phones GPS."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gm26sa
|
Why aren't objects bent in videos where the frequency of said objects is the same as the camera shutter speed?
|
The title won't make sense if I don't explain as I barely understand the basics. I have recently learned about the rolling shutter effect from this video: URL_1 I have seen several posts here on reddit illustrating what happens when the camera shutter is the same as for example the blades of a helicopter. I get that the blades appear to not move but why I don't get is why the blades aren't frozen and also bent as seen in the rolling shutter effect. Example of helicopter blades for example: URL_0
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr12ddd"
],
"text": [
"The rolling shutter effect is only visible in certain conditions. Some more expensive cameras have a global shutter option instead of a rolling shutter. And whith a global shutter you do not get the rolling shutter effect. Another way to get rid of the rolling shutter effect is to increase the shutter speed so there is less movement in the frame as the rolling shutter is moving across it. So it is quite likely that they have used camera settings that does not show the rolling shutter effect when filming the helicopter blades. Either they are using equipment with a global shutter or they are filming it on a bright day with a faster shutter so the effect is not so visible."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gmb7rm
|
how transistors become a microprocessor?
|
So I was wondering how multiple transistors coordinate to become a microprocessor.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr2wc7j",
"fr2pt8c"
],
"text": [
"First thing you need is a clock. Something which goes from 1 to 0 and back again repeatedly. This is provided by an external oscillator. Now you have to keep track of this time in order to know when to do things. To count the time you arrange the transistors into a counter, this is tricky and most digital designers surprisingly would not know how to make d type flip flops from individual transistors, it's all in feedback, but I digress. Once you can count the clock, you can read instructions for the microprocessors instruction memory, which tells you which connections to make to the different blocks (memory, arithmetic blocks) and the rest is quite straight forward. The counter points to the next \"thing to do\" i.e instruction which says \"add a and b\" so you make connections which place a and b into the inputs to the processors calculator and hit go, the clock ticks, you count to the next instruction which tells you to connect the output from the alu to a piece of memory. These \"connections\" are the transistors themselves. Instructions are 1s and 0s which go into the \"on/off\" control pin of a transistor, which can be arranged into \"gates\" which can be built into functions. The magic behind microprocessors is the clock, keeing track of this allows you to run a sequence, which makes use of a set of fixed functional blocks to do an incredibly wide variety of tasks.",
"Transistors do not coordinate anything. Transistors are only building blocks for making circuits that take one set of bits (0's and 1's) and produce another set of bits, precisely according to specification. With enough circuits like that connected to each other, you can perform an operation and obtain useful result after turning the power on. Transistors are just there to control flow of electricity, everything we understand as computing is done logically, on more abstract level."
],
"score": [
7,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gmdews
|
How do bar codes work?
|
The entire system is complete wizardry to me. The laser itself is witchcraft but the most amazing part is the database. I could imagine that stores somehow associate a code with a product when they add it to their inventory system but what prevents two manufacturers from using the same bar codes on different products. Is there a master database somewhere and who is responsible for managing it? Edit: I really appreciate all the answers about the database aspect of this but I am still wondering how the actual laser works. Seems like it has to be fairly simple because the technology has been around for decades, long before 'modern' computers.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr2yzvv",
"fr36bqi",
"fr2yjs8"
],
"text": [
"When a manufacturer produces a product it has to pay for each of those number codes that are attached to the bar code scanned at checkout. Yes each product has a unique barcode for itself. From type and size (think different size boxes of the same cereal at the store) the manufacturer pays for them. It’s a long number too right? It can be broken down like a phone number with area code first...it is more specific than that though. Starting with the general product type, then country it was manufactured in, then the manufacturer’s company code, then that specific products code. The bars above the number are kind of like a number code for the laser to read. The size and spacing represent separate numbers. Pretty cool and a universally accepted way to track purchases, keep stock of an inventory, and maintain the extensive catalog of products out there. 😊",
"UPC has manufacturer ID prefixes. The first 6 digits of the number just identify the manufacturer. So lets say you are a new company wanting to make products. You register with the UPC database and your company gets assigned the value, let's say, 999123. All your products must start with those digits. You can have a product called 9991230000000001, then your next product is called 9991230000000002, then your next one you call 9991230000000003, then maybe you make a jump and on a whim you call the next one 999123000050000. You can do whatever you want with the numbers 999123000000000 through 999123999999999, but must keep your products in that range, because 999122xxxxxxxxx and 999124xxxxxxxxx will be some other companys' ranges. (There are several versions of UPC, some are less digits and some are more, but for all of them, the FIRST 6 have to be your company's ID so you don't clash with anyone else.) There are many universal ID number systems that have the same kind of problem: like the MAC hardware address of network interfaces (that 12 hexidecimal thing you see in your network config options some times). They solve them the same exact way - by assigning a range of numbers to a manfacturer and there's penalties and fines for using a number outside your assigned range.",
"UPC - Universal Product Code. Don’t know the specifics but you have to apply and get a code for your product. Hence, “universal”."
],
"score": [
15,
10,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gmgeqf
|
Why can't we charge phones faster?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr3hqaj"
],
"text": [
"Think of a battery energy supply as a straw in a glass. smaller straws deliver power slower, but then imagine your glass has to be refilled with the same staw being used as the power supply. & #x200B; Phones are smaller batteries that don't have a lot of power output, and as such, it takes them a long time to recharge. You can stress this a little bit, but it's very much like pressurizing the straw, you can't do it for very much more."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gmgk8r
|
Why is anticheat so hard to implement in games
|
Aimbot for example. It seems to me that all that would be needed is a counter for accuracy to tag someone for aimbot usage yet most AAA games are still plagued with cheaters.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr3ik83",
"fr3j8cw"
],
"text": [
"It's a constant game of cat and mouse. A simple counter works perfectly until somebody figures out it kicks in once you've hit X straight headshots and programs their bot to only hit X-1.",
"No matter how clever you think you are as a developer, the hackers are cleverer. Depending how you look at it the hackers also out number the development team so they have more resources. It's a constant game of figuring out what the hackers are doing, how are they able to do that, and patching the code to block that particular vulnerability. That can be a lot harder than you think to accomplish."
],
"score": [
11,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gmhe0y
|
Why was it that, back in the early days of the WWW, some browsers would load a low-res image which would then become sharper, while others loaded the image bit-by-bit, top to bottom?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr3sirg",
"fr3o8l6"
],
"text": [
"This is not depending on the browser, but the image. If it is stored as “progressive JPEG”, a lower resolution version can be shown first because the first bytes of the file contain a rough version which then gets more detailed when more data is available as download progresses. With increased download speeds, progressive JPEG fell a little bit out of fashion because it was no longer necessary.",
"That's a feature of jpeg. Somewhat simplified jpeg encodes images in blocks of 8x8 pixels. It computes a discrete cosine transform of those blocks and quantizes the resulting coefficients. An interesting side effect is that one of those transformed values happens to be the average value of the 8x8 block. So by putting all of those values at the front of the file you can get a low res approximation before having downloaded the entire file."
],
"score": [
3,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gmoaez
|
How your antivirus knows what to look out for.
|
I've always been curious as to how fast the people that work for antivirus software companies need to work in order to keep their customers safe. How do they identify threats and patch their software to achieve a safe experience for their customers
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr4qiz3",
"fr4qv52"
],
"text": [
"- they look for known malware. they have these databases of what they have found out there and tell their software to check for those. that's why your antivirus should always be up to date and also constantly needs to download updates. - to create those databases they usually have some form of \"exposed & advertised machine\" (think of it as a mailaccount that actually REGISTERS for spam and has no antivirus) and check what lands there (obviously it's more complex than this, but just as a rough idea) - the antivirus software checks for \"weird/suspicious behaviour\". Your \"myholidaypicture.jpg.exe\" that you got per mail already is suspicious because \".exe\" means it's not a picture. or that word-dokument you got wants to access a site on the internet and download stuff right after you open it. - sometimes they miss stuff. and sometimes they miss stuff in their own software and (because an antivirus needs very deep access to your system) create the backdoor the virus uses to infect in the first place. In conclusion: - use some software to help you vs viruses (the pre-installed windows defender is already really good and can compete with most other antivirus programms) - always update your antivirus, this is really really important. - try to keep your wits about you: that ad offering you a downloadable file to claim your prize/check your system/make your pc faster? malware. that weird mail that doesn't fit what you'd expect from the sender and upon closer inspection reveals peculiarities? probably malware. dont click stuff if you dont know where it's been. it might be dirty.",
"New threats are reviewed for its behaviors and a \"fingerprint\" is created for it, called a signature. AV companies release signature files that are used to review behaviors on your device to see if they match a \"fingerprint\". First, an unwanted behavior has to be discovered. This \"unknown behavior\" period of time is where \"zero day\" malware lives."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gmoduz
|
How were stars on the far side of the sun discovered?
|
As the earth is in orbit the sun's light with drown out the light of stars in that direction from the earth, so would there be different stars in the night sky depending on what time of year it is? I'm not astronomically with it and can't seem to wrap my head around the idea since the north star is known for being at the same point in the sky every night
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr4pyw5",
"fr4qb7g",
"fr4q1wl"
],
"text": [
"Stars don't move much, so you just wait a few months when the earth is on the other side of the sun.",
"We orbit around the sun, so whatever stars are on the opposite side of the sun to us now will be on the same side of the sun to us in 6 months. Stars like the north star appear relatively static because they are \"above\" the Earth relative to that orbit. Imagine you are laying down on a merry-go-round. Now place balloons on the ground around the edge, and also tie a balloon to the center of it. As you spin, which balloons on the ground are nearest your head will change, obviously, but the balloon in the center, above your head, will stay in relatively the same point in your field of vision.",
"You do realize the earth orbits around the sun, right? So a different set of stars would be hidden behind the sun at different months of the year. The North Star is just so far away that even though we are moving and rotating, it's position doesn't really shift much from our vantage point."
],
"score": [
20,
5,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gmtous
|
What are the light circles that appear when taking a picture of the sun?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr5nnq8"
],
"text": [
"Lens flares. The camera has multiple lenses. Even the cleanest lens will only let through 98% of the light and it won't do it perfectly. Some of the light is absorbed, some is reflected. The sun is bright [citation needed] so the reflections are bright too."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gmx7t9
|
Why are games on PC’s able to change settings to best suit the machine, but those same changes aren’t available to console players who could also benefit from them?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr69coy",
"fr69hpz",
"fr6j3x9"
],
"text": [
"Because PC's represent a huge range of possible combinations of hardware that the game has to adapt to, but every X-Box in the world has the same hardware.",
"Because theres a LARGE variance in PC specs. Someones college laptop is going to have very difference specs than a high end gaming computer or someone into video editing. & #x200B; Generally the key difference in consoles is memory, but otherwise, the manufacturers of the games produce their games around the specs of the consoles.",
"Consoles want to make sure every player gets the same experience. This leads to capped frames and locked in settings with the graphics. The good news is this means a competitive advantage online is coming entirely from the player and a fairly limited set of hardware for the vast majority. It also means the consoles can monitor their games for cheating and easily ban them."
],
"score": [
13,
5,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gmzry7
|
Why, in classic style Disney movies, can you see which part of the shot is going to move or fall away?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr6ru8v",
"fr6pnfo"
],
"text": [
"This happens whenever the moving things and the background are drawn/painted in different mediums. In older cartoons, the backgrounds were usually paintings, but the things that moved were black-and-white ink drawings on clear celluloid, with the colours painted on the back, which made the colours flat and brighter-looking and more cartoony. So, if they wanted to have some part of the background move, like a bush, without having it be a flat drawing, they would have to essentially do a bunch of little paintings for every frame, and that would not only take too long, but painters tend not to be animators and animators tend not to be painters. So they had to compromise and have the moving bush (or tree, or pile of rocks, or section of a wall) be a flat cartoon. On TVTropes they call this the [conspicuously light patch]( URL_0 ). Sometimes on bigger-budget productions with more staff, they would have effects animators who knew how to animate things without black outlines and flat colours, but even then it wouldn’t usually look like a regular painting. On some shows however, like *The Simpsons*, the backgrounds were on back-painted celluloid too, so they could mostly avoid this problem. Of course now it’s all digital.",
"Sometimes to save time and money the animator will use a still image duplicated over and over for the parts of the frame which never move. Then they do their individual frame by frame animation for the parts that do move. Modern cartoons are a lot better at blending the two images, while older cartoons using older equipment and techniques sometimes had trouble getting them to blend."
],
"score": [
9,
3
],
"text_urls": [
[
"https://tvtropes.org/pmwiki/pmwiki.php/Main/ConspicuouslyLightPatch"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gn03de
|
How much more powerful are movie industry standard computers used for CGI, than a $3000 home gaming PC? Is there a limit to how much processing they can do?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr6ruta",
"fr6vt7t"
],
"text": [
"In most cases, a *render farm* will be dozens to hundreds of nodes. It's hard to pin down what \"gaming-level\" means exactly, but each node's performance is certainly a lot closer to the PC under your desk than a massive supercomputer. It's more efficient to break down tasks that way, due to how the rendering processes work.",
"The final version is rendered on hundreds of computers networked together in a render farm. While working on the CG they use a lower quality version of their assests they can work with in real time. Sometimes it's very real time. There's a video from Infinity War showing an overlay of Thanos face over the actor so they could see a lower quality image of how the CG face will look. The Mandalorian uses a partial CG set where they have the rendered image displayed on giant screens on set. This allows everybody to see what the CG environment look like, and lights the physical set properly at the same time. Render time is measured in hours per frame, but they can work on multiple scenes at the same time. If you look at the credits after a Marvel movie you'll see a lot of visual effects studios work on the movies."
],
"score": [
11,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gn44kn
|
What is the Y2K bug and how would it have led to computer havoc?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr7h0cn",
"fr7lttx"
],
"text": [
"[You’re looking for Wikipedia mate. ]( URL_0 ) Basically, in the 1970s computers were originally so dumb they decided to save space by only using 2 digits for the year. All the computer people knew this would need to be fixed before 2000 but that was decades off. The computer people continually warned the business people of this upcoming problem but the business people didn’t want to spend money to fix something they didn’t have to yet and it became the next guy’s problem. The late 90s roll around and the computer people realize they’re gonna need public support to get the business people to shell out for the upgrade. Now everyone know about the problem and starts panicking (as they should) because at midnight New Years 1999/2000 the governments, banks, airplanes, hospitals, and a gazillion other systems are all going to try to do calculations thinking it’s 1900. Thankfully because the governments and businesses finally got around to taking the computer people seriously, nothing bad actually happened. Unfortunately uneducated people will often joke about y2k like it was a hoax or scam because nothing happened. It was not. It took a lot of work by a lot of people to prevent tragedy.",
"Contrary to popular perception, Y2K could and did actually do some damage. Not world ending damage, but some, and it could have been worse. In the past computer memory and storage was much more costly. So they had to save all the money they could. So rather than writing a year like 1997, they would write 97 in the computer. The problem is that 2000 would read as 00, so the computer would think 1900 was written. This caused many problems. For example: Say you run an automated warehouse, you got a brand new product that expires some time in 2000. Your automated warehouse computer reads 01-01-00, thinks \"It's 01-01-1997 right now, this thing expired in 01-01-1900, better throw it away it's 97 years out of date\" Or something like compound interest, your bank computer says \"you put a deposit in 1997, it's now 1900, calculate the interest based on -97 years\" This would probably result in a garbage answer coming out. So on and so forth. The thing is a bunch of these happened before the year 2000 came around, and most were fixed by the time it did. A lot of computers didn't use the last two digits of the year at all. They used a system where they counted the number of seconds since January 1st, 1970. So the year 2000 was not really all that different from the year 1999 by that system. But funny story, they used 32 bits of memory to count the seconds. On 03:14:07 UTC on 19 January 2038, all the positive bits will be filled, meaning the whole thing is going to roll over and flip into negative. So when dealing with dates past that, you'd get a date and time in 1901. Fortunately most modern systems now used 64-bits, so we're good for the next few hundred billion years. Unfortunately, a computer that was made as part of a machine, and then put someplace you can't get at , like in a nuclear reactor or launched into space, might still have an old 32 bit time definition. So things are probably going to be interesting in about 18 years."
],
"score": [
5,
3
],
"text_urls": [
[
"https://en.m.wikipedia.org/wiki/Year_2000_problem"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gn4765
|
How does Apple Face ID work in the dark?
|
Basically how does the camera recognize my face when there’s almost no light, or is there? (Dim screen light maybe?)
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr7guit",
"fr7mg29"
],
"text": [
"It uses infrared which can’t be seen by our eyes. It’s the same thing that night vision goggles use.",
"It shines infrared light onto your face that the camera picks up. If you had another camera and pointed it at your face while using face ID, you'd see dots being shone onto your face [example]( URL_0 )"
],
"score": [
12,
8
],
"text_urls": [
[],
[
"https://forums.macrumors.com/threads/photo-face-id-infrared-dot-matrix.2084242/"
]
]
}
|
[
"url"
] |
[
"url"
] |
gn4m6g
|
How does my computer know how long a second is?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr7js1x",
"fr7kg98"
],
"text": [
"Computers have a tiny little oscillator in them. This oscillator vibrates at a set frequency - a certain number of vibrations per second. This is controlled by the shape and material of the oscillator - since it is always quartz the shape is really all that matters. This tells the computer how often it should do computations, as well as how long a second is.",
"Your computer's independent time keeping is about as accurate as a quartz watch from the 1970s - which is actually very, very good. However, it most likely syncs automatically with internet NTP servers to avoid drift. There's a better chance of this mechanism messing up than the quartz and onboard battery."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gn57eq
|
VPNs. Are they for people to do illegal stuff on? How do they work? Why would I want one or not?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr7pnkb",
"fr7q68b",
"fr7ty6a",
"fr7pdhs"
],
"text": [
"A VPN can be used to form a private tunnel trough the internet for protecting the data you need to transfer. Imagine you are making a video game and your team is spread around the world in different countries. Your team members need access to the game source code, which is of course a tightly guarded secret so your competitors cannot steal your cool new groundbreaking video game. Making that source code available to the internet, even if it's protected by a password, is dangerous. There's a possibility of someone cracking your password or intercepting the data as someone on your team accesses it. What you want is that only people inside your private network can access the source code. You cannot have a physical private network because your team is not in the same location, so you create a Virtual Private Network or VPN for short. By having access to your virtual network, your team can safely access the source code trough the VPN tunnel without anyone being able to intercept it. Edit: Thanks u/derpdederpmustang",
"There are many legal reasons for people to use VPNs. I'm using one right now due to work from home to talk with my company's computers. Normally when you send something over the internet, you break it up into little packets, electronically write down where you want it to go, then send it off. VPN stands for Virtual Private Network. So rather than just sending the package. You wrap the whole package into another encrypted package with the VPN server's address, and then send that over the internet. The package is encrypted so only you and the VPN server can read it. The VPN server opens the packages, and then sends it. So why is this important? Say you want to have your company computers safe from the internet. Simple, you put them on a network not connected directly to the internet. Or you tell them to ignore all packages that do certain things, unless they come from a very short list of trusted computers. Then you make the VPN server either connected to that network or on that short list. The VPN server figured out you're you through some security system. It sure what you sent is real, because only the two of you know the encryption. So it sends the stuff to the hidden computer and you get stuff back. Now say you want to talk with a website that has garbage security, everything is out in the open. But you just connected to a random coffee shop wifi, you don't know if the wifi hot spot is reading everything you send and making changes to steal your stuff. With the VPN, the coffee shop thief wifi only see an encrypted package, it knows you want to send something to the VPN, but can't tell what you sent or where it's going to wind up. It can't send you a fake package back, because it doesn't know the encryption you and the VPN were using. Now we enter into the less legal realm. Say you have a server that only talks to servers on the same country, like saay it's a tv network's streaming service for America. You are in France, if you try to access it, it sees you're in France, and doesn't let you. But you have a VPN server in America, so you connect to that. Just like the company VPN in the first example, the tv network computer can't tell. The VPN server is in America, so it thinks the request is coming from inside america, and sends you the stuff.",
"A VPN is a way to securely send messages between two different computer networks across a public network. That's not very ELI5, so let's try this: You're on a playground. All your friends are on the same playground, and so you can all talk to each other. If you want to find Billy, he's over by the swings. Sally's over by the slide, etc, etc. This is a local network, like your house or your office has. There are other playgrounds - each of them has people hanging out by the slides, hanging out by the swings... it's all just like your playground. But you can't really talk to them, since they're all on different playgrounds. You can get to different playgrounds by going on the public streets. This is the internet. Your mom tells you not to do that, though, because the creepy neighbor with the weird mustache watches everything you do. He doesn't ever touch you, but he does watch really closely... he says it's so he can figure out what you like and send you letters later about stuff you like and might want to buy. But he promises he won't ever do anything bad with that. His name is Mark Z, but he wants you call him something cooler than that. Anyway, one day you realize you have friends at two different playgrounds, and you'd really like to be able to talk to everyone at *both* playgrounds, but you don't want to have to run up and down the street. You get yourself a set of walkie-talkies! Those are expensive, so you can only afford one set, but really 1 set is all you need. If you need to talk to \"Sally by the slide at Playground 2\", you can just radio up whoever has the walkie talkie at playground 2 and tell them to go pass a message to Sally. Really it makes sense to put one kid at each playground on radio duty for they day. This is a simplified explanation of a site-to-site VPN - usually you see these when you're connecting multiple offices together. Now you have another problem - all the messages you're sending back and forth can be heard by anyone with a walkie talkie on your channel. You might be discussing super-secret birthday plans, or maybe you-know-that-jenkins-has-a-huuuuuge-crush-on-sally-right?! You don't want Mark Z to start sending you weird letters about it, or even worse, tell Sally about the whole Jenkins thing. That would ruin all the fun. So you develop a secret code that only the kid with the radio can unscramble. This keeps eavesdroppers out, and is basically how encryption works. That's the second part of the VPN - now my 2 playgrounds (networks) can talk to each other directly over public radio waves, by using a secret code to keep everything secure. A client-to-gateway VPN is a slightly different critter. Let's say Johnny is home with the flu, but he has his *own* walkie talkie! He can still join in the fun, as long as we tell him the code. It's like he's at the playground with us! Usually this is how things like traveling salesmen get connected to their office's network even when they're out visiting their customers. There are also a whole bunch of VPN services out there you can subscribe to. They're all client-to-gateway VPNs of one flavor or another. To stick with our playground analogy, they let you pretend to be at any one of a few hundred playgrounds all around the world! So lets get to what I suspect is your real question: Why? 1, Privacy. Since you can pretend to come from any playground you want, it makes it harder for Old Man Z to listen in to all the things you like and send you weird letters all the time. It's not 100%, since he's figuring out how to check things like which radio you're using, but it's better than nothing. 2, For business reasons (or if you're loaded and have 2 houses...) , you may want to connect multiple offices together. You don't want your rivals to see your data back and forth either. 3, Avoiding geo-locking. Back to the playgrounds - it turns out the local video store will only rent that one movie you want to people from playground 62. They promise they'll let you rent it some other time, but for now it's playground 62 only (think US netflix vs Canadian netflix). If you can pretend to be from Playground 62 by using your walkie talkie, you can totally rent that new movie! 4, Security From Government. Yes, you might be running illegal stuff in your wagon between playgrounds and want to make sure Police Officer Jones can't see it. But you also might be living in a place where all the public streets have a police officer on them who's a real jackass and hits kids with his nightstick if they say anything bad about him. For places with totalitarian governments, VPNs can be a way to safely let the outside world know what's going on. This is why China's trying to outlaw them. 5, Security From Other Kids on the Playground: OK, you're *probably* not a target, but I've worked on systems where it turns out a jealous ex was sniffing traffic to see what his former partner was up to. This is probably tinfoil hattery for most users, but honestly, it comes up occasionally. I'm glossing over a huuuuge amount of detail here, and the honest truth is most of the VPN subscription services don't actually do anything useful. On the other hand, understanding and implementing VPNs is essential for businesses to allow remote work and connect multiple sites together.",
"Imagine you want to send a letter to Bob, but you don’t want him to know it was you who sent it. Maybe you want to send or request something illegal, or perhaps you just don’t want the him to know where you live. So, you hire Alice and she agrees to send the letter to Bob for you in her name. First, you send Alice the letter, and then she sends it to Bob on your behalf, promising that she’ll forward you any response that Bob returns. There are other elements to it, but that is a VPN in a nutshell. Instead of letters, we’re exchanging data over the internet. It can be used to do illegal things, but sometimes it’s just used by those who want privacy. Your IP address can map pretty close to your physical location, so maybe you just don’t want to reveal that to every entity you interact with over the internet. There are other reasons to have a VPN as well. Employers, for instance, usually require connecting to a VPN in order to access certain company data on its “private network.” The comparison in this case is that perhaps a receiver Alice only trusts letters that come from a particular address, so you’re not able to get a response from her. But, luckily you know Bob, who has an address that Alice trusts. So, you send the letters to Bob and he sends them to Alice. When Alice responds, Bob sends you her message."
],
"score": [
66,
23,
16,
8
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gn664v
|
- how do supermarket anti-theft scanners work?
|
How do the scanners at the exits for supermarkets and stores tell if an item hasn’t been paid for? Is it something to do with the barcodes on the item or something?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr7zolz"
],
"text": [
"It's mostly security theater. The anti-theft scanners react to specific security tags that are not found on most items. They aren't looking for barcodes or anything like that. If an item has some form of security tag attached that wasn't removed by the cashier or deactivated by the cash register, then the security tag trips the sensors at the door and the alarm goes off. But 90% of items in general stores or supermarkets don't have any security tags because they aren't considered high-ticket or high-theft items. So if you try to walk out of a store with a TV in the box, or a bottle of perfume, or a DVD without paying, it will probably set off the door alarms because they are likely to have security devices that need to be removed or deactivated at the point of sale. But if you are walking out with a cart full of groceries you didn't pay for, the odds of something in your cart having a security device in it are very very low, so the alarms probably won't go off. I explain the different types of security devices and how they work below, if you're interested. Specific high-theft items will have a security tag or sticker attached to the product, or they might be secured inside a security package. They can either be something that gets removed at the point of sale (cash register) by the cashier or deactivated, usually with a sensor pad installed into the cash register where the scanner is. If the security device is not removed or deactivated, it will set off the alarms at the door, where there are usually pedestals or partitions, or sometimes sensors embedded in the door frame, which sense when a security device is near. They're kind of like magnets, if the live security device gets too close and the sensors pick up on it, it sets off the alarm. A common example of security devices that get deactivated when scanned at the register would be small, narrow, kinda padded white rectangle stickers (they aren't just flat, they stick up off the product a bit) that are commonly stuck on DVDs, CDs, and perfume. They can either be applied by store associates after receiving the product from the warehouse, or they could be applied inside the packaging by the manufacturer. These are pretty durable plastic stickers, but they are just stickers after all, so they're not the best way to prevent theft because it's not very hard to peel them off. Security packages are the kind that would need to be removed at the cash register, usually requiring some kind of key or magnet to unlock them. At the company I worked for we used Spider Wire and Keeper Boxes. Spider wire is basically a double loop of wire that goes through a sensor/alarm disc that wraps around a box (like a classic Christmas ribbon on a box) and you can tighten the wires around the box so it is snug enough that the wires can't be pulled off by hand, you need a special ket to unlock the alarm disc to loosen the wires. We used this for big boxes, like TVs, computers, printers, expensive toys, etc. Keeper boxes are durable plastic boxes in a variety of sizes that have hinged lids that lock when closed and require a special key to unlock. We used these for perfume, some expense makeups, DVDs, printer ink, pretty much anything cereal box size or smaller that was an item that got stolen a lot. If tampered with, both types contain an audible alarm. So you can't use wire cutters to snip off a spider wire because it will scream and it is LOUD, and same with trying to pry the lid open on a keeper box. Clothing stores tend to use smaller tags that are basically like 2 discs that have wire needles between them that lock together when pressed together, forming like a sandwich. Because of the needles, you can put one disc on each side of a piece of fabric and press the discs together into a sandwich and then the fabric is caught between. Some of these have built in alarms like the spider wire and keeper boxes, some have dye packs that explode if tampered with. Both kinds set off sensors at the door, to my knowledge, although we didn't use them much so I'm not an expert on those. All of these items have to be removed at the cash register or by some other store associate who has the key to unlock them, or they will set off the alarm at the door."
],
"score": [
12
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gn7h93
|
how does Bluetooth and internet wireless routers transfer data "over the air"?
|
I have heard that is something to do with waves but it always goes over my head how they manage to transfer data over it and how fast it happens.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr82cfv",
"fr84xe2"
],
"text": [
"The means of transportations are electromagnetic waves, produced by photons. They are the same as light, and light as you may know moves in waves, just like waves in the sea. There is also the concept of \"wavelength\", which basically means how long the \"bulge\" of a wave extends. Now your eyes cannot see the signals of Bluetooth or WiFi, because they can only detect certain wavelengths. However we can build devices who can produce electromagnetic waves in a certain wavelength, and we can produce different devices that can receive them, antennas. (I don't know the term for the underlying concept of senders, so excuse that please). So your router has a sender and your phone has an antenna to receive these electromagnetic waves. That's how that works in principle. Then on top of this there happens some magic, for example modulation. Modulation means manipulating the wavelength and frequency (how often a wave occurs in a set interval) so that these modulations can carry information. We need this because a wave itself carries no real means of information, or more precisely modulation offers us to convey more information than just \"signal there, signal not there\". With these two principles we can basically transmit data from sender to receiver. After this there happens a lot of \"computer science\" in that we agree connections, employ protocols and such. But that's another topic.",
"Super simplified: Imagine you are in an empty swimming pool with your friend. You on one end and him on the other. When you move you will cause waves that your friend can see. If you move faster you will cause more waves. And with the way you move you might be able to alter the form of the waves. Now you can agree on a code with your friend. For example one wave could mean \"Bring me ice cream\". You could then agree on more codes that also take into account how many waves you make in a minute, what form they have and so on."
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gn9509
|
How does a thermal camera work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr898vl"
],
"text": [
"You know how hot things can glow red and very hot things might even glow white hot. The same effect works with colder things as well. But instead of glowing in red they glow in infrared. A thermal camera is a camera which does not capture the regular red, green and blue color bands but rather captures several infrared color bands. And by looking at what colors of infrared they glow it can determine what the temperatures are."
],
"score": [
19
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gn9yrr
|
How do servers find our computers to communicate over the internet?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr8d6qr",
"fr8d8vj"
],
"text": [
"Your computer is the one that finds the server by looking it up via the phonebook (DNS registry). You computer also sends its own address with the message so the server can reply.",
"Largely the servers don't find you. You find the servers and they reply back. The way that works is DNS, which converts names like \" URL_0 \" into their IP address. Then routers all over the world exchange maps of where IP address blocks are and each router will pass your data off in the general direction of the intended server. Your request will include your own IP address as the sender making replies find their way back via the same method. These details are covered at length already."
],
"score": [
18,
7
],
"text_urls": [
[],
[
"reddit.com"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
gnae6i
|
how an MRI machine works?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr8n2gs"
],
"text": [
"Your body is full of water, which contains a particular element: hydrogen. The funny thing about this element is that it spins round at a particular speed, and this speed increases when the magnetic field it's placed in increases in strength. So when you put a glass of water in a strong magnetic field, many of these atoms align with the field and spin round. Now the cool thing is that when you send an electromagnetic pulse into that atom at the exact frequency as it's spinning, you get it back. So this enables you to detect water in your scanner.. still not very useful. But because the spin is dependent on the strength of the magnetic field, smaller magnets within the scanner sort off distort the field a little bit in three directions.. this way atoms at the top, bottom, left, right and front and back are distinguishable. Another neat thing about it is that the degree to which you get a signal of these hydrogen atoms depends a lot on their environment.. whether they're surrounded by fat, air or other water molecules. This gives you differences in signal intensity, and can be used to create contrast. Now the scanner has a big computer to process all this information.. what signal came from where, what was left and what was right. So if you move, even a little bit, these calculations get messed up. And depending on the desired resolution of your signal, it can take a long time for the MRI to go through your body and sample bits of spinning atoms."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gne24a
|
What was the reason for the rotary dial on vintage phones?
|
This might be a silly question, but is there a technological or mechanical limitation that prevented them from having buttons for numbers? Is it an example of [skeuomorphism]( URL_0 ), was it actually easier for people a hundred years ago to use than a number pad, or did buttons just not occur to anyone?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr93kfh",
"fr9r55f",
"fr93b0n",
"fr945di"
],
"text": [
"The way that rotary phones worked is that you'd pull the wheel to the desired digit and then release. There was a spring in the wheel that would cause it to release at a specific speed. While it was releasing, it opened and closed a switch at a specific rate. So the farther you pulled, the more \"pulses\" the switch would create. That's what the phone system was looking for - the pattern of pulses. Touchtone dialing doesn't use pulses, it uses audio signals of a specific frequency (each key corresponds to a specific frequency.) That technology was invented after rotary dialing.",
"In the earliest days of telephones, you picked up the phone which opened (actually closed) an electrical circuit with the local switchboard . At the other end the operator would pick up. You told her who you wanted to talk to, she would call them and once they picked up she'd connect your line to theirs and you could then talk to each other. As you can imagine this was sort of cumbersome, especially as more people started getting phones installed in their homes and businesses. If you wanted to make a long distance call, this might involve several operators getting involved. Later analog relay switches were developed along with the rotary dial phone. As others have explained, when you dialed the phone, this sent a series of electrical pulses out across the phone line. Now, instead of an operator picking up and directing your call, based on the series of electrical pulses received at the local telephone interchange, the phone system would automatically direct your call. This was all done using electrical relays, etc. In the 1960's the phone company began to computerize its systems and the modern DTMF tone system started to roll out. The phone company's computer recognizes the tone and converts it to a number. You actually got charged more for have a pushbutton phone. As the older analog relay/switching system started to be phased out the computerized system took over. Today you can still use an old dial phone on most phone systems. The computer at the other end will still recognize the electrical pulses and convert them to numbers to connect you to whomever you're calling.",
"There is only one pair of wires. You could have buttons, but you need to convert that button press into a series of pulses to send down the one wire. For the \"7\" button, you need to send a stream of 7 pulses over about 1 second. Making a mechanical clockwork mechanism to do this would be very, very expensive. Even the best mechanical watches of the era used a rotary stem to set the hands rather than buttons. So, buttons are expensive and hard to the point of being unpractical, and rotary dial was cheap and easy. It wasn't even a serious contest.",
"The dial was hooked up to send a little electrical \"pulse\" through the phone line every time it passed a number. The farther the dial spun, the more pulses. So if you dialed a six, it would spin back to its rest position and give off six pulses. If you dialed a 9, nine pulses, and so on. The phone system knew what phone number you were dialing by counting pulses. For this reason the fancy name for old rotary phones is *dial pulse* phones. Button phones worked on a different system called *touch tone*. Each number was coded to a \"boop\" noise with its own specific tone. So if you dialed a number quickly you would hear a \"beep boop beep bip boop\" series of tones. The technology for the phone system to understand these different tones wasn't created until the 1960s."
],
"score": [
12,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gng4xp
|
What is Ray tracing?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr9h3e9"
],
"text": [
"Literally. Tracing rays of light. Pick a light source and then fire \"rays\" out of it and light up the environment like that, while also programming surfaces to reflect said rays in a realistic way. Thus getting incredibly realistic looking surfaces and \"god rays\" etc."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gnhvv2
|
- in light of all our advances in wireless technology, why are printers still such a pain point in operating with devices?
|
I know that things are much better than they used to be, but given the seamless integration we have across so many other devices these days, both hardware and software — I feel as though the amount of average technical issues we face with printers to this day is much higher than it should be.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fr9sxxp",
"fraxm5v",
"frad095",
"fr9rtub",
"frbj926",
"fra3295"
],
"text": [
"The problem isn't technology, it's standardization. Look through your list of print drivers and there are 1000's. It's hard to make anything work with that large of a group, especially when they are all doing their own thing. Until a market leader emerges and standardizes the system, printing will be a pain.",
"Connecting to a printer over wireless is honestly a bit of a gimmick. Printers will shutdown frequently by design to save power, and spend most of their lives sitting idle. This makes them terribly ill-suited to be hooked up to wifi and should always be hard wired. Printers are one of these strange things in the computer industry that fight standardization. There is absolutely no reason that printer drivers, consumables, and hardware can't be widely standardized other than the manufacturers actively fight against such things. Printers are such big money that their manufacturers like it this way. Constantly changing models, parts, and most importantly their associated cartridges and toners, forces customers to buy more and more of the product. The real money in printers is the consumables. Paper and ink/toner. Everything about the market is designed around selling more consumables. Consumer printers are designed to be so cheap as to be effectively disposable. They exist only as a method of making you buy extremely marked up ink cartridges. Commercial printers are far more expensive, complex, and reliable (by amount printed) and big money is made selling lease agreements and consumable contracts. Big companies pay contracted fees for consumables like toner, paper, and maintenance.",
"Most computer components have few or no moving parts. A printer has many. This makes it more prone to mechanical problems - jams and so on. Competing and conflicting standards for how the output is described to the printer - PCL versus Postscript, leaves lots of room for bugs and conflicts. Generally information technology is incredibly standardized - far more than any other industry ever conceived, so this is not the case with other computer components. Thousands of models - again, lots of room for unique problems and conflicts. Lastly - people. People want to feed envelops and A4 and letter sized and heavy paper, light paper, sticky paper, glossy paper. How many varieties of DVD can you put in a burner? How many sizes? And does anyone ever turn a DVD on its side to load it in differently? No. But paper - every day they frig with the machine. And technology - ink jet versus laser - ink jet has the illusion of superiority due to better colour and lower initial price, but the technology is fundamentally crap. But people buy them for the way the pictures look before the ink dries out and head jams up. Load your printer with 8.5x11 20lb bright white. Print with one driver - PCL or Postscript, I don’t care, and use a laser printer. If a picture prints blank, switch to the other driver type. (PCL versus postscript). You will be printing for years between problems.",
"I'd say it depends of the quality of printer you're buying, can't expect to have the same compatibility/ease of use of a 30$ printer than a 200$ one... I bought a 200$ wireless laser printer a couple years back and have no problem printing from my phones/tablets/computers",
"Are they? I have a brother laser printer that works wirelessly with my PC, Mac, and everyone’s phones. No one has had any problems with it. It just works. Brother lasers are the bomb. Second one I’ve had, and the first one still works great, we just wanted to upgrade to wireless for convenience.",
"In all manufacturing, every decimal of precision required adds a zero to the price point. Also, every unique part adds to the base cost because each requires a separate mold and milling detail. The first rule of Mechanical Engineering is \"If it moves, it will break\". So, moving parts need to be tougher to resist a certain amount of movements over the design lifetime of the printer. Then there's ink. Any inconsistency in the ink fluid that wasn't filtered out in the processing or developed in shipping will gum up the tubing. Bigger tubing lets the gunk flow through, but nozzles can only be as thick as the smallest letter. Same principles apply for laserjet dust. Again, better filtering = more money. And what is a printer? A box full of fiddly little moving parts pumping ink through very small tubing that everyone wants as cheap as possible. Unless you kick out for an expensive printer with good production standards, you're going to be dealing with a good deal of bullshit."
],
"score": [
42,
7,
5,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gnkvvr
|
On Google you can see the usage of a word over the past century or so. Why do words sometime have a figure stating that a word like "PayPal" is used from 1890-1910? I know that Google looks at archived data. So where is this information coming from?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fraeqku",
"fracf54"
],
"text": [
"One thing I've noticed at the Internet Archive is that you might get hits for, say, the Watergate scandal in the 1920s. When you check the book you find that it's a work from the 1920s that was reprinted in the 1980s with a 1986 introduction that mentions Watergate. Also, many works are misdated. At the Archive you find lots of magazines that are dated, say 1956, but are actually from a completely different decade. Google might have similar problems.",
"Old books and newspapers and manuscripts are often digitally scanned and converted into text by a program that can recognize letters. It's not perfect, and sometimes it will make mistakes. Maybe there was something that actually said \"pupil\" or \"purple\" or \"platypus\" or something and the algorithm read \"paypal.\""
],
"score": [
19,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gnond8
|
What does a remote have to "see" the TV?
|
Why can't the signal go through a blanket or shirt?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"fraylyv",
"frayiyn",
"frayqi2"
],
"text": [
"It's actually the opposite. The TV has to see the remote. That bulb on the front of the remote is a light. It's infrared so your eyes can't see it, but most phone cameras can actually see a little into that spectrum. Look at a remote with your phone camera and press a button, and you'll see it light up. The TV has a little camera looking for that light flickering in a specific pattern to change channels.",
"It’s just a tiny burst of infrared light. So if the material it needs to go through absorbs it, the sensor at the TV can’t catch and read it. The first remotes used sound instead of light but you can imagine they were pretty limited in functionality.",
"Remotes use infared leds to send and receive electronic messages between the remote and the tv. Infared light behaves mostly the same way as any other light, except humans can't see it. So you may not realize it because you can't see it anyway, but blocking the remote or the tv receiver will mean the light can't get through to send the electronic message between the two."
],
"score": [
22,
6,
5
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gnp45g
|
- What happens to email after we delete it from our trash folder? Is it gone forever? Can it be retrieved by hackers or law enforcement without our consent?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frb2lh8",
"frb3c1u"
],
"text": [
"It's been a hot minute, but iirc deleted files have a coded metadata that gives them a hardlink to a storage department. What deleting from the trash folder does is completely remove that hardlink to make it \"invisible\" (without some software). **So, the information is not gone and could be retrieved using various pieces of software or hardware.** I am unsure of the process, it's been a long time and have forgotten that information. So, could it be retrieved by hackers? Yeah, it could. I assume dataminers would be able to retrieve those files unless the files were shredded or formatted.",
"Depending on your mail system, it can remain after deleting. For the most part, any file deletion removes references to the file, noting its space is available, but doesn’t necessarily clean that drive space. If your mail system uses a database or single files for mail “folders,” it’s probably gone after the next emails arrive to use the space. These are very common mechanisms, and most mail servers operate that way. The big file system has allocated space that it will reuse to remove files. For example, if this paragraph represented a mail folder, and each sentence a message, deleting the second sentence wouldn’t leave a gap, but would rewrite with the rest in its place. This might leave some of the last sentence remaining in unused disk space, though. If your mail system uses multiple files, it will probably be quickly overwritten, but that depends on the file system, the media, and volume of files written on the system. If each message is a separate file, a file system may forget the references to the file, but then skip it until a right-sized file came along to replace it. Either way, emptying your mail trash can will probably leave a bunch of stuff on your drive, until the space is needed again. The fastest way to do that with single files is to set the size of the file to zero, or maybe a very small header in some systems. Also, remember that the mail itself may travel through more than one mail server, and may be stored on each as the server processes the messages passing through them. There may also be file system back-ups that could contain the messages. Eventually, all of the systems involved will “forget about” that file, and recycle that disk space. How fast depends on how busy. It’s really hard to delete things on the internet."
],
"score": [
6,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gnpasf
|
- How does Youtube decide which videos have an ad play before the video?
|
I have been watching more videos lately and I can’t help but wonder why some videos have an ad prior to the video playing and others (often from the same content creator) don’t. I watch videos via a Roku connected to a TV if that matters.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frb3bgx"
],
"text": [
"It's partially left up to the creators I believe. Beyond that, they have a software system running that scans through videos looking for things that would mark it to be demonetized, meaning it is content that advertisers probably wouldn't want to be associated with by having an ad play on it. Further, they just might not have an ad available to serve at that moment that seems to fit the bill of the content."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
gntbcx
|
What is the darkweb, and why can’t you access it from google?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frbs5cs",
"frc3x9x"
],
"text": [
"The 'darkweb' is just a buzz word. It literally means the park of the internet that isn't indexed by search engines. That's right, Google and whomever doesnt know everything! Back in the day you used to have to know the actual url of the website or you could not go there, there was no other way to find it. In base terms you do not need any special browsers, you do not need tor (onion networks are just a subset and would require another question around their purpose and anonymity pursuits). Now people have packaged darkweb browsers, but get this because this is the funny part, these browser just have a home page that is an index of these unindexed websites. The bundled browser itself is basically the result you would want from a search engine.",
"The darkweb is, in practice, a buzzword more than anything. You have 3 levels: Clearnet - This is your regular internet you can access from anywhere with a regular browser (Chrome, Safari, Edge) Facebook, Google, Youtube, etc. Deep web - This is simply a part of the internet that is not indexed, or, colloquially, cannot be found on a search engine. Many parts of the deep web are accessable through clearnet browsers, you just have to know the url you need and manually type it. Dark web - The dark web specifically refers to many .onion sites, of which you need a special browser (Tor) to access. It is similar in appearance to the clearnet, albeit a LOT slower (by design) and more empty (no ads or scripts running). All there really is (I've spent a lot of time exploring what I can of it) are hidden wikis, the same porn you find on clearnet, marketplaces (similar to an early Ebay layout) for drugs, and there probably is CP on it sporadically. I did come across links that claimed to have it, but obviously, I'm not gonna check that. You cannot access it from google because clearnet browsers won't resolve .onion urls. Allow me to also make it clear; Any video you've watched, or story you've read, that has sensationalized it (dark web) beyond simply buying drugs and maybe finding a little CP if you're really dedicated, is 100% completely *false*. There are no big \"bugchasing forums\", no websites selling child sex slaves, or hiring hitmen, or none of that bullshit. They said it for views and completely made it up. You don't have to take my word for it, though. It's perfectly legal to access & browse the dark web (except watching CP, but they really couldn't catch you unless you were in a honeypot or your OPSEC was poor.) You can find plenty of .onion links to browse from the clearnet."
],
"score": [
13,
11
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gnusza
|
- How can we download a game without downloading the source code.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frbymlx",
"frc00pm"
],
"text": [
"Source code gets transformed (by a compiler) into something the target platform can understand and run. What you’re asking is kind of like asking why can we follow an English translation of a French recipe without having the French recipe (assuming you read/write English and don’t understand French).",
"> *THERE IS MORE ELI5 VERSION DOWN!* The main point of Programming languages is to make machine code that CPU executes, more readable and understandable to humans, so we can code more efficiently and more complex applications. But because source code is intended to be \"human readable\", CPU doesn't understand it. So in order to execute source code on CPU the source needs to be compiled to machine code that CPU understands. But vice versa, the machine code is hard to read for humans. So programs including games that you download are compiled, and there are tools that allow you to look at the code, but because it's compiled you and even most of the programmers won't understand it easily. You can also convert machine code to source code, but then things like comments in the original code are lost during compilation and the code will also look different than the original. So now although it will be in some human readable programing language, still it will be hard to understand what code does, without comments and original structure it was written in. More ELI5 part: Legend: Cake - compiled program, Ingredients - computer resources, Recipe - source code (how to utilize computer resources), Eat the cake - execute the program. Imagine you bake a cake with help of ingredients and recipe, so you end up with the delicious cake. You then give the cake to some other person, and they can eat it (run the program). But now they wonder how did you make such delicious cake, they could ask you for recipe, but they don't want to. So instead they bring cake to laboratory and ask how the cake was made. Now in laboratory that can tell you the composition of cakes, which molecules and compounds are there and how much, now they can suggest to you how the cake was *probably* made (this is like decompiled code), based on knowledge of how other cakes (programs) are usually made, but they can't tell you exactly what was the original recipe, how exactly it was originally done. Kind of like that secret Coca-Cola ingredient that only 3 people in the world know and no one else can figure it out."
],
"score": [
10,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gnwgjc
|
Why do ISP’s exist? Why can we just connect to the internet without them? What stops us? What’s limits us?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frc7e30",
"frc7p6r",
"frc83d6",
"frc8v3x",
"frc9630"
],
"text": [
"How are you gonna connect to the internet? You don't have a wire that goes from your house to reddit's servers which are hosted on Amazon's data centers. That's what the ISP provides. That wire.",
"ISPs *are* the Internet. For you to be able to access something on the Internet, lets say Reddit, there needs to be a connection between you and Reddit's server. You have a connection to your ISP, which has a connection to a larger ISP, which has a connection to other ISPs, and so on and so on, until you get to the ISP which Reddit's server is connected to. So even if you try and skip the middle man and avoid paying a consumer ISP, you're still going to have to deal with ISPs because everything else on the Internet is connected via an ISP of some sort.",
"What’s stopping us? Nothing, really, but I don’t think the average person have enough money to run a cable to every server on the planet. The point of isps is that they do the expensive part and let you connect to them so you are also connected to everything they are connected to",
"The internet is literally that. A large group of interconnected networks. Roger's has a group of ip addresses bell has them Verizon has them. It's just a more modern version of the phone company with phone numbers. These ISP have neighbours and share information between their neighbours on how to get from point a to point b. Your ISP generally has 2 peers for redundancy which are other isp and eventually one of those peers has uplink to major providers such as level 3",
"ISPs shoulder the cost of building and maintaining the global networks, which includes hundreds of thousands of kilometers of very expensive wiring and optical cables, plus the multi-billion dollar equipment of routers, network switches, DNS servers, etc. that handle the management of network traffic. Wanna gofundme a thousand kilometer ocean floor cable?"
],
"score": [
21,
20,
10,
6,
4
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
gnx9eg
|
Why Ip address exist on the internet and why we need them?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frccgb6",
"frcehnc"
],
"text": [
"The IP address is kind of like a phone number: it identifies a single connection, a phone number identifies a phone connection, an IP identifies an internet connection You don’t often see them because you use the URL instead of the ip, that works like a phone book, you loop up the address and you find the phone number to call, but it’s done automatically",
"IP Addresses are kind of like phone numbers or house addresses. You need to be able to specify what server you want to go to. (You typically use domain names, but DNS acts like a phone book, translating a friendly name into a practical address/number). One of the important things about IP Addresses is routing them. If every router needed to know every single other address, they would not be sustainable. Instead, IP Addresses can be generalized. (This whole example is going to use private IP Addresses just to be easier. If you know enough to realize this, you know enough to not care that I'm doing it). For instance, an ISP that operators across all of the US might have the range of addresses \"10.0.0.0\" to \"10.255.255.255\". Rather than just scatter them all around the US, they will do something more intelligent, like \"10.0.0.0\" to \"10.3.255.255\" are reserved Florida, and maybe \"10.128.0.0\" to \"10.191.255.255\" are reserved for California, among others. Now, all the routers in its network don't need to know every possible address in Florida or California to send the packet in the right direction, they just need to know what range of addresses to send along what path. This is sort of similar to how, when you mail a letter, they're not going to look at the street address right away. First, they'll make sure it's in the right country, and then the right state/province/county, and then the right city, and then finally they'll put it in the proper couriers bag for the address."
],
"score": [
9,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
go4302
|
Why do ads load better and faster than the video you’re trying to watch?
|
When I’m trying to watch a video, an ad will load right away and play flawlessly in the beginning. But when the ad is done, the video sometimes takes awhile to load and play (even if it’s a minute long video like the ad was). I understand some of that may be due to internet issues, but is there something else going on?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frdlj1b"
],
"text": [
"There are often several copies of the same ad stored in servers all over the place, and only one or two copies of your video. This is because each ad gets viewed by many more people than each video. Since there are more copies of the ad, odds are you'll be closer to one of them than to a copy of your video, and so the ad loads faster."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
go7cd5
|
Why do video games often crash when they have too many things on screen at once?
|
Frame rate almost always drops but many times the game will crash as well. Why does this occur?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"freel38"
],
"text": [
"Wow first time I’ve been able to answer one of these. You won’t be able to generalize this to every game, but for the most part this causes the program to run out of memory. Every object on the screen needs to be tracked in memory, programs (and computers in general) have a limited amount of memory and when that limit is reached and the program tries to use more execution will fail causing the game to crash."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
go87rx
|
- Why, when on a slow connection, does a video often manage to play through once, but have difficulty replaying?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frebkxj"
],
"text": [
"Depending on the size of the video, your device's memory, and sometimes on the video player and video format, your computer/tablet/phone might not be holding the *entire* video in memory for instant replay. It's often the case, when streaming for example, for the video player to only hold 10 or 15 or 30 seconds of previous video in memory (often called the \"buffer\"). Which means, if you go back further than that, your computer will need to redownload that information again before it can be viewed. Other factors can be at play too; or some of the previous suggestions may not need be worried at all - it very much depends on a few details. But they are the most likely things to be encountered by the layman"
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
go8kgc
|
How do bots work?
|
Like for example the bots on you tube that either show you some thing in your recommended feed, or to make sure your a human. One, what else can they do like to an extent what is the most a bot can do, and two, if I had my own like if I paid some one and they give me the code for the said bots what could I tell them to do, like for example could they run a business, or do simple tasks?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frefokw",
"fremb9u"
],
"text": [
"A bot is just another name for a computer program. It takes some form of input and performs some action. Reddit bot programs take reddit posts as input and do behaviors like automoderator for too short an answer and removed the answer and sends you a DM",
"YouTube bots feed your watch history into different algorithms (like video_recommendation= watched_videos /disliked_topic). They use machine learning and nueral networks for that."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
gobxl5
|
What exactly is being done during a routine server maintenance?
|
And why does this help server stability? (aka: why does Steam basically shut down every tuesday)
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"frf05vx"
],
"text": [
"Essentially, repair work. Like when you take a car in for an oil change & routine maintenance: it can't be used during that time, but taking it \"down\" for the maintenance will help it run longer and better in the long run. Specifics depend on the server structure, the company, and what needs to be done. For online games and services, sometimes they're updating code (which could cause problems for users who are online if they tried to do it live). Generally speaking, they could be replacing hardware, running system updates/upgrades, sweeping the floor under the server racks, it could be caused by maintenance being done on any of the providers used by the server's keepers (Planned electrical or internet provider outage, though major systems will have backups upon backups to deal with that; server maintenance by their website host; etc), any number of things. Most big systems (like Steam!) offer some kind of \"this is what we changed\" list -- maintenance logs, client updates, something along those lines. For Steam, here's the latest update log: URL_1 And a more general explanation by them of what they're doing: URL_0"
],
"score": [
4
],
"text_urls": [
[
"https://support.steampowered.com/kb_article.php?ref=7366-ETYS-5919",
"https://store.steampowered.com/news/?feed=steam_client"
]
]
}
|
[
"url"
] |
[
"url"
] |
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