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6mojge | how does Alt+f4 work when closing down a program and is it any different from closing it from the task manager? | Technology | explainlikeimfive | {
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"Alt+f4 is the same as clicking the little x button at the corner of the window. What it does is send a message to the program saying \"please close\". Depending on the program's code, it can comply and shut down, it can show a message box to the user asking if they're sure, and it could even ignore the message altogether. The program can do some cleanup before actually shutting down. When you click \"end task\" in the task manager, the operating system closes the program forcefully. It doesn't give the program a say, and it doesn't let it run any more code, so the program can't do any cleanup or save its current data.",
"In Windows, Alt-F4 sends a message to the program telling it to shut down. This is the same as what happens when you click the close button (The red X at the top right), or select \"End Task\" in Task Manager. However, when you instead use \"End Process\" in Task Manager, Windows kills the program immediately, without asking the application to shut itself down. This will end a stuck/crashed program, but could corrupt files that the program was in the middle of writing to, and the program won't be able to save data it had in memory. As a test, open up Notepad, type in some text, and try to close it using these four methods. When using the close button, Alt-F4, or End Task, Notepad will ask you if you want to save first. If you End Process on notepad.exe, then it'll just close and the text you typed will be lost."
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6moqxh | Why hard disks become slower with time? | I have some HDs that were in notebooks and desktops, that the read/write speeds are < 3MB/s while access time seems to be around normal values (can't remember the actual values). SMART values are normal according to some softwares, so I don't know what happens. At the same time I have a 1.5TB drive that reads/writes at 80% the original speed, and has over 44k hours on it (used as storage for video recording, system backups, etc) | Technology | explainlikeimfive | {
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"There are a couple reasons. Hard Disc drives have a plate in them. They start in the center and write till they get filled on the outside. When you put information on the drive, it records where it put the data on the innermost layer and then has to move to the outer most layer to place the data. Same thing with finding the data etc. Picture going to a filing cabinet and pulling out a list of Files and where they are. Its easy when the list is small and the information you need is right next to the list. But as you get more files, the list grows and files are stored everywhere. The second part of this is HDs right to first available space, so parts of a file can be scattered around the drive. The more you add and delete stuff the more fragmented the drive becomes. This is why they recommend running DeFrag as it puts the files next to each other. to make reading faster. So the nature of having more data, the possibility of a fragmented file system can cause things to run slower, it happens over time."
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6mp5bw | Why are virus/spam websites not more powerful? | I code off and on and I've always wondered why spam websites that include a pop-up "virus" require you to click on said pop-up box before they can actually inject something into your computer. Could they not just call a virus on page load instead of actually needing a click from the user? | Technology | explainlikeimfive | {
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"It is a lot safer and easier to trick a dumb user into clicking something than it is to run an exploit. The exploit might tip off the antivirus, crash the machine or otherwise alert the user to the presence of the virus. A fully patched and updated machine will also be immune to any exploits these viruses might try to use, if there is an exploit that is newer than the latest patches and that nobody is aware of then it is a zero-day vulnerability and that is far too valuable to waste in a silly little virus. It will be used in something more serious or sold on the black market for thousands."
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6mpbbt | How do drones steady themselves? | Technology | explainlikeimfive | {
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"Quad copters need gyroscopes to fly. If the gyroscope detects that the quad copter is starting to lean in one direction the electronics will speed up that propeller and decrease the speed of the opposite propeller so the quad copter stops its movement."
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6mprmw | theres a youtube error where you get a wall of random letters and they say show it to the monkeys, how does this work? | if you need an example, URL_0 | Technology | explainlikeimfive | {
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"It's an encrypted error message. The server had a problem and spat out a detailed log of everything it thinks might be relevant, but they don't want to show all those details to the general public. It's possible in theory someone could use that information to figure out how to routinely screw up their servers, or access something they shouldn't. So the server encrypts it before showing you, then their support team presumably has the decryption key. This is why they want you to copy/paste and not screenshot, because if it's a screenshot they'd actually have to type all that jibberish into the decryption tool instead of just pasting it, and ain't nobody got time for that."
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6mq6vm | Why can't you use laptop parts for a PC? | I know you can use some parts like RAM but what about the CPU and other junk. | Technology | explainlikeimfive | {
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"Everything in a laptop is shrunk down to reduce size, weight & heat. Laptop CPUs are generally soldered on rather than socketed. GPUs are either integrated into the CPU or soldered onto the board as well. Laptop motherboards are generally a custom form factor, not something you can mount in a regular case. Most laptop memory uses a different physical standard than desktop memory. HDD/SSD drives are one of the few things you can reuse. Even laptop CD/DVD/BRD drives are designed to be stuck inside a laptop case rather than sit in a desktop's drive bays.",
"You could, in theory. The problem is that a laptop motherboard and a desktop motherboard are very different, and you would have a lot of trouble trying to connect laptop parts at all, never mind the firmware issues that I'm sure exist but don't know enough about to talk about. It's a round hole/square peg type of problem.",
"Laptop buyers want portability, which includes little weight, possibly a thin design, long battery life, little noise and little heat. Those things preclude using parts that demand more power (they'd empty the battery a lot sooner) and also means you can't use large heatsinks and coolers which dissipate the component's heat better than slimmer heatsinks and fans (as there is less metal to absorb the heat and less air to remove it). Desktops, OTOH, aren't meant to be used with a battery, are generally expected to be larger and have more power available: a typical laptop uses 65 watts, while gaming desktops can be designed to demand ten times that power. That means you can use larger components, those components can demand more power and there is far more room to dissipate a lot more heat. So parts are designed differently: laptop parts are more compact and generally less powerful (ie, a Kabylake desktop i5 is more powerful than a Kabylake laptop i5) than their desktop counterparts. What you can use are laptop hard drivers in a desktop pc. The larger 3.5\" desktop hard drives wouldn't fit inside a laptop though (due power consumption and their bigger size. A laptop with a 3.5\" hard drive is something consumers would not want: it would be thicker and the battery would last less). Laptop optical drives use slightly smaller connectors, but there are adapters to use them with desktop computers, although you won't be able to easily place it inside a desktop case. All other parts, including cpu and ram can't be fitted in a desktop motherboard (although some small form factor mothers do use laptop ram)"
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6mqetx | What's the resolution on a human eyeball? At what point will this HD/Ultra 4k race surpass what our eyes can notice as an improvement? | Technology | explainlikeimfive | {
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"1 arc minute 20/20 vision is having an angular resolution of 1 arc minute(1/60th of a degree), but this is only true for your central vision, it falls off rapidly the further out you go We've pretty much hit the point where resolution doesn't really matter. Phone screens are exceeding 300 DPI, to distinguish individual dots your eye needs to be really close to the phone but then it can't focus anyway. The higher resolutions will come in handy for VR headsets though, as they are much closer to your eye they need a much higher pixel density to maintain the same angular resolution",
"Standard definition TV was designed to roughly match 20/20 vision when viewed at 7 times screen height. For Full HD it's 3 times screen height which means 1.5 times screen height for 4K and 0.75 times screen height for 8K. So, if you have a 60\" TV and 20/20 vision, here's a guide to how close you need to sit to take full advantage of the pixels: * 720 & times;480 (NTSC): 21 feet * 1920 & times;1080 (Full HD): 7.4 feet * 3840 & times;2160 (4K): 3.7 feet * 7680 & times;4320 (8K): 1.8 feet If you're sitting farther back than that then you're not taking full advantage of the available resolution. Young people might have better vision (maybe 20/15) and be able to sit back a little farther. So 8K is only useful for very immersive experiences where the screen takes up a huge percentage of your field of view. You'll only be taking full advantage of the resolution for the part of the image that's in the centre of your field of view, but you can always look around to see detail wherever you want in the image.",
"The first Iron Man was the first BluRay I watched on an HD screen and I remember thinking: if it gets any better looking than this, I don't think my eyes could even tell. Since that thought, I always wondered what the limits of a human eyeball are, what it can reproduce for us, and how much better technology could do with metal and electricity than meat and tissue does with its evolution. The eventual destination of my original question - can we make things look \"better\" than they do in real life? Granted, certain nature photos look better than I would recognize a bird or bug to appear on my own if it were right in front of me, but you get what I'm saying I think.",
"The race is to light field displays. You know how a screen and a mirror (or window) look different? That is because mirrors are emitting different photons in different directions, while a screen is just blasting the same light out at every point. A few more doublings, and we can simulate an actual window to somewhere else."
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6mqhey | Why do we have both AM and FM radio frequencies? What are the differences between them? | Technology | explainlikeimfive | {
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"AM is an older technology. It's like shining a light across a field and to communicate you make it brighter and dimmer. The problem is, fog or dust or a dog in front of the light could change the brightness, making it appear like a \"valid\" signal but also making it wrong. Some frequencies have been set aside for AM use. Many specific rules and regulations are \"accidental\", just because it was use before FM. FM is a newer technology. It's like shining a light across a field and changing the color. Red dust may block green light but it won't *change its color to red*, so instead of a wrong signal you get signal loss. And most interference will reduce brightness, but you'd be able to see and identify different colors just fine. So it's very robust, even if you get interference you tend to lose the signal instead of misinterpret it. FM is used for higher-quality broadcasts and there are restrictions on which specific radio frequencies use FM. Again, this is partly historical, legal, and political. In the United States, the lower frequencies used for AM fundamentally limit quality (in addition to AM's own limitations) but are good for long distance. Good for news, weather, emergency use. FM has better quality but is more local for a number of reasons. Good for music."
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6mrdb0 | how casinos can have people smoking inside and not have smoke detectors go off | Technology | explainlikeimfive | {
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"Smoke detectors are only one type of fire detection device and there are different types with different sensitivities. Some measure the actual amount of smoke particles via ionization and some measure the clarity of a photoelectric beam. Some do both. Rate of rise sensors are temperature monitors that look for the sudden increases in temperature that are consistent with incipient fires. All 3 types would be used and set based on the amount of ambient smoke in the air around the detectors."
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6mrwfl | How are airlines so good at scheduling flights that almost every single one is fully booked? | I've been on 46 commercial aircraft over the past 4 years, and only one of them was not at least 97% full. What type of things do airline companies use to determine when to schedule flights that will get the most bookings? Note: I'm not asking why an airline would want to do that or how overbooking works (like other threads have answered), I'm asking how airline companies know their flights will be fully booked. | Technology | explainlikeimfive | {
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"There are two main ways: First, they have a lot of data from being in business for many years. They can look at how many people flew from New York to Houston on every flight they've flown between those two cities for the last 10 years and see if there are trends for which flights are full, which are empty, what times of day are preferred, etc. Flights that consistently aren't full can be cut or have their scheduling changed. Second, they adjust the prices for flights constantly. If you've ever looked at the price for a flight over the course of a couple weeks, it regularly changes from day to day. Part of that is due to who is buying flights when (price-sensitive recreational travelers tend to book well in advance, price-insensitive business travelers tend to book closer to the flight time), but a big portion of it is making sure the flight ends up full. If the flight isn't selling as many tickets as they want it to, they can lower the price, whereas if it's selling more tickets than they expect, they can raise the price. They keep doing that right up until flight time (even advertising sales and such things very close to flight time if the flights are really underbooked) to try to ensure they sell every seat while maximizing revenue from those seats.",
"They use demand pricing. If a plane isn't full, they drop the seat prices, until someone says, \"I will take the 6 am flight\" or \"I'll leave on Thursday instead of Friday\" if it means saving $300. At the same time, the price on the full flights go up. If what is usually a $200 flight to Vegas is now $600, you are apt to seek out one of those emptier flights."
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6mslkn | Why do commercial planes fly on same altitudes running into possibility to hit each other and needing flight controllers? | Why don't they utilize many different hights? Same with paths - can't they go farther to the left or right on the way back? EDIT: Thanks everyone for your answers. | Technology | explainlikeimfive | {
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"They do indeed use different altitudes and paths, so any collision in mid-route is already unlikely. But there are thousands of aircraft in the air at the same time. And the most crowded areas are near airports, where all airplanes *must* converge on a single altitude and a tiny number of paths to use the runways.",
"Ok, so here's a comprehensive answer! (And keeping it ELI5 as best I can) Aircraft do in fact utilise many heights and paths. Aircraft mostly travel on \"highways\" in the sky (much like you do in a car). Now these highways keep all aircraft moving in an orderly fashion which makes it easier to keep aircraft apart. On these paths, aircraft often fly to one side of the path, especially on longer flights, to avoid being close together! (From memory it's about 5 nautical miles to the left where I'm from). [Take a look at this website called skyvector]( URL_1 ). On the top right of the map, click **World Hi** button and zoom in to see some of these highways. Now for altitudes. Aircraft do fly at many different altitudes and are actually required to fly *odd* altitudes (like 33,000FT or 37,000FT) when flying *north or east*. If flying *south or west*, then - you got it - even altitudes. The altitude an aircraft flies at depends on how much traffic there is and what the aircraft can actually fly best at. Generally, most airliners fly between about 30,000FT and 41,000FT as at these altitudes the aircraft are more efficient. Not all aircraft go that high - especially if the flight is short. And for really long flights, the aircraft is heavy enough that it is too inefficient to fly very high and so will often fly at a lower altitude for a third of the flight, climb to a new altitude for another third, and then once again to another for the last third. [Look at this flight to see what I mean]( URL_2 )[(and the altitude graph)]( URL_0 ). Hopefully this answers your questions? Ask more and I'll answer! Edit: Formating"
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6mudna | So a CPU is just a bunch of switches, either being "on" = 1, or "off" = 0. But "who" or what decides when a switch should be "0" or "1", in order to make a useful computation? | The more switches (or rather transistors) a CPU has, the faster it will be. The clock speed (i.e. 3 GHz) determines how many times per second all those transistors will make a computation. But what system controls all those billions of switches each cycle, so that the CPU outputs the right string of 1s and 0s which results in a perfectly rendered dank meme? | Technology | explainlikeimfive | {
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"I'll try to give an eli5 but keep in mind it's an highly abstracted answer which grows in complexity step by step. To answer your question you need to look at the structure of the CPU itself. 1. we'll start from a **transistor** that like you said act as a **switch**. it can transmit electric power (logic '1') or block it (logic '0'). 2. arranging those switches in a specific structure gives you a **[logic gate]( URL_0 )**. the basic gates are called: **NOT, OR, AND** and they translate one state of their input to another state of their output. NOT (0- > 1, 1- > 0), OR(00- > 0, 01- > 1, 10- > 1, 11- > 1), AND(00- > 0, 01- > 0, 10- > 0, 11- > 1) 3. arranging those gates together in a bigger structure can give you more complex gates such as **NAND,NOR,XOR,XNOR**, each with it's own translating function. 4. arranging those complex gates together can also give you a **[memory cell]( URL_1 that can store the state of '0' or '1' over time. (keeping the output the same while ignoring change in the input) 5. combining memory cells together with logic gates gives you a **[state machine]( URL_2 )**. the state machine look at it's input and current state in memory and decide what the output and the next state of the machine should be. 6. and finally we got to **the CPU** itself which consist of some logic (big structure of logic gates that do some specific function) and a complex state machine the control how the CPU should work and what logic function should be activated in the current cycle of the machine. -------- last note: 7. this description will not be complete without considering the **software** part of things. a software is a set of instructions that is stored in memory. each instruction is represented by binary code consists from '1' and '0'. for example \"0101 1111 1101\". 8. the state machine inside the CPU (the one that control and choose the logic to be used) runs in a loop that is called an **instruction cycle**. each instruction cycle consist of 3 stages: **fetch, decode, execute**. fetch means to read the next software instruction from memory. decode means to decode what this instruction means. for example 0101 in the instruction above means add two numbers. the numbers are 1111 and 1101. and execute means to activate the needed logic in order to make the computation. in this example the state machine will activate the logic that can add two numbers. -------- so **tl;dr**: the cpu has a state machine (lots of switches) inside of it that toggle all the other logic (lots of other switches) and do the work that the software ('1' and '0' in memory) tells it to do. and you get your dank meme.",
"The person who built the processor - for example Intel - decides what each combination means. The CPU understands a language called \"machine code\". Machine code is made up of a series of 0s and 1s. There is a command called MOV, which moves a piece of data from one place to another. MOV isn't actually machine code, because it's not 0s and 1s - it's something roughly equivalent to machine code but (slightly) more human-readable called \"assembly language\" The machine code equivalent of MOV is 10001001. (Actually, there are lots of variants of MOV, and this is the first half of one of the variants, but I'm trying to keep it simple.) This code was decided by Intel. They could have chosen any code they wanted, but this was the code that they chose. So they built a group of switches so that there are a group of 8 wires, and when the 1st, 5th and 8th of those wires all have a signal on them, but the others don't, the switches turn on the \"move\" circuit. Then, they built thousands of other groups of switches that work in a similar way. They also built switches that actually do the moving, or the adding, or the subtracting, or whatever else needs to be done, and connected them up so that they get turned on and off when they're required.",
"Trying to describe a CPU directly with switches is like trying to explain why bacon tastes good with protons and electrons. You first need to understand how the smaller components are organized into larger, more complex ones, on multiple levels. We start with transistors, which can act as switches. A handful of switches can be used to make logic gates. They typically have two or more inputs and one output. The ouput represents a basic logical operation on the inputs, like AND or OR, or more commonly the negated version, NAND and NOR. A handful of logic gates can be used to form basic digital circuits. A flip-flop circuit can store a single binary digit, and an adder can add two binary digits together. Chaining eight of these together lets you perform operations on bytes. Digital circuits can be used to create the building blocks of the CPU. The arithmetic logic unit (ALU) performs basic data manipulation operations. The memory unit moves data from memory to cache, and cache to registers, where it can be operated on directly by the rest of the CPU. The control unit loads instructions from memory, then interprets the instructions as a sequence of memory and ALU operations.",
"\"Like you're five\"... It's going to be impossible to provide an accurate answer to a five year old, so let me give you a similar question that has an answer a five year old can understand: How does a car know where to go? A car is just a bunch of gears and belts, but who or what decides if it should go left or right or faster or slower? What the car does depends on what the driver does. If the driver turns the steering wheel, there's basically a series of gears and belts that push and pull each other so that the two front wheels change the direction they are pointing. If the driver presses the brake levers, those levers push other things that eventually push the brakes onto the wheels. The levers and gears and belts and wheels are built so that when one lever or wheel is moved a certain way, it moves a whole bunch of other stuff that causes the intended result. You could call the collects of gears and belts and so on \"systems\" in the car. The systems are structured so that the gears push each other as they should. There are also systems in a CPU. CPU systems are set up so that when a 1 goes in at a certain spot, and a 0 at another spot, and another 0 at a third spot (these would be inputs), they produce a series of 0s and 1s somewhere else (outputs). This would be like a person turning the steering wheel left while pressing the gas (inputs). The car moves to the left (output). It's the structure (the shape and positioning of the parts of the CPU) that make it turn inputs into outputs. So fundamentally, what makes the CPU produce 1 and 0s? The structure of the CPU. Going much beyond that requires you be at least 6 to understand the answer.",
"This is a very complicated topic, but the early videos in[ this video series]( URL_0 ) explains it rather well.",
"It depends on the gates the current flows through. If a high voltage goes through a not gate, it returns a low voltage (a^l =x). If 2 currents go though an or gate, and at least 1 is high, it returns a high voltage (a+b=x). Else, it returns low. There's a bunch of different types of gates that will return high or low voltages depending on the inputs. This will probably get me reported to the moderators, but here's a link that will go into more detail and will explain more gates: URL_0",
"So the answer to this question is basically an undergraduate major. But maybe one approach to help you understand is to look at a very basic pseudocode and see how it turns into machine code and see how the machine handles the machine code. > result = 1 + 1 > print result simple right? in my pretend assembly language (each architecture has its own assembly language, which is basically a human readable representation of machine code) my code might turn into this: > add 1,1,r1 > push r1 > jump print the assembly code has an intermediate step where those names are translated into physical values. > add 1,1,0x1 > push 0x1 > jump 0x8 i'll explain what exactly happened here in a bit. but further translating this into machine code you might get something like: > 00 01 01 01 > 01 01 0000 > 10 1000 00 So now you can sort of describe this in terms of switches. The first two ones and zeros are the control part. they determine where the rest of the signal goes. they do this with a variety of and/or gates combined in a special way to give a unique output for each possible combination (in this scenario, there are 4 possible paths, 00, 01, 10, 11 - just because of how i designed the machine code) this is called a multiplexer. so whenever the first two bits are 00, the rest go to the adder circuit in our cpu, which only has the function to add two numbers. the two numbers are the next 4 signals, each number being 2 bits so it can be either 0,1,2 or 3. here we are adding 1+1. the last two bits are what i earlier called \"r1\" for register. its just a piece of memory. it again goes to a multiplexer and enables writing to that particular register (we have 4 registers because its a 2 bit address) though the physical wires will be connected to all the memory spots. \"enabling\" a write is just another sort of manipulation of and/or gates. you can look at the next instruction now, and see the first two bits are different. that means they go to a totally different circuit, which operates on the same principles as above. holy crap im bad at explaining to 5 year olds so i'll stop the post now",
"There are two main components that decide: the clock and the control module. They make use of the memory and arithmetic logic unit (ALU) components. When you turn on the computer, electricity flows to the clock (a crystal oscillator) which starts to vibrate at a constant rate. These vibrations are measured where part of the vibration cycle is output as a 1 and the other part output as a 0. Circuits can be built to only change their output when an input switches values, and only during the switch. By attaching the clock to this input, the circuits' output is synchronized to the clock. That is, the clock input could be held at 0 or 1, it could switch from 1 to 0, and all other inputs could be random values, the output will not change. Only when the clock switches from 0 to 1 will the output be updated depending on all other inputs. The control module decides what to do next and its initial state would be to fetch an instruction from the first position in memory (because its instruction pointer (IP) would be 0) and switch to decode mode. This step would commit on the clock cycle. On the next clock cycle, now in decode mode, it would use the fetched instruction to set all other switches needed to execute that instruction and switch to execute mode. I think on this step (or maybe the end of the previous step) it also asks the ALU to add 1 to the IP. Finally, on the next cycle, it would commit the instruction itself updating memory and return the state to fetch mode. Now, back in fetch mode, the next instruction would be from memory address 1 (because the ALU added 1 to the IP). However, the executed instruction may also have modified the IP, which allows the instructions in memory to implement loops and conditional instructions, where it can \"jump\" over other instructions. Once all this is in place, the computer may have the first memory address be a ROM chip that asks a loader to be read from a specific portion of the main hard-drive (or whatever the BIOS is configured to use). An operating system may put their OS's loader here, the OS basically being one big loop that keeps the computer running while it's on.",
"Computer programs are sequences of CPU instructions. Each instruction tells the CPU to do one specific thing it can do, like load a value from memory or add two numbers together or jump to another instruction. In principle, the CPU reads in an instruction, executes it, then reads the next instruction and executes that, over and over again until it loses power. (In practice it's more complicated because of pipelining and branch prediction and all sorts of other things that are used for efficiency, but it produces the same results as if it ran each instruction one at a time, just much faster.) Of course, that sometimes leads into a second question, which is how the whole chain gets set off. Sure, when there's a program running the CPU can read instructions and execute them, but how does it start? That's the job of the computer's firmware (historically BIOS, nowadays usually UEFI), which is a small hardcoded program whose first instruction is automatically loaded when the computer turns on. That program does a few bookkeeping things (checks some settings, validates that the hardware is working, etc) and then loads another program from a fixed location on the hard drive. That program then starts up the operating system and then your computer is off and running."
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6mugvf | How did the cameras that were used during the moon landing work? How were they able to broadcast relatively clear picture and sound from space, using 1960s technology? | I ask this because there is a group of people who think the moon landing *itself* is real but the tv broadcast was staged. I personally don't believe that the broadcast was fake, but the question piqued my curiosity and I would like to know how it worked. | Technology | explainlikeimfive | {
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"Basically, the important thing in space communications is not the size or power of the transmitter, but the sensitivity of the receiver. Once you have compensated for local issues like atmosphere, other radio sources, the rotation and revolution of the Earth, etc, then the only thing that affects the transmission is distance, and we have lots of distributed, really sensitive receivers to pick up weak signals.",
"It's actually higher quality then what you're used to seeing. The Neil Armstrong first walk is actually a TV recording, pointed at a monitor, because they didn't have a slow scan TV adapter. The camera feed from that was recorded, but the tape of the video coming from the lander has been lost. Only the people in Australia saw it at full-quality, ever thing else is a copy. Australia boosted the signal and sent it to the US. People at NASA saw the boosted signal, and that was also recorded to make the public TV feed. See URL_2 for details. You can see a good photo of what the screen looked like showing the live image, and how high quality the images were. If you're intrested in how they got the radio signal, it was picked up at the URL_1 . That little brick building that the dish is resting on... is a 3 story building. That telescope is huge. Watch URL_0 If you're interested in a dramatized version of it.",
"* there is very little interference in space...if light reflected from the sun can get to the earth, so can radio signals * being the government, they weren't restricted by licensing or the FCC, they could use the best frequency for the job * the orbiter boosted, focused, and directed the signal * giant radio antennas, not rabbit ears, were used to receive the signal",
"The same tech that's behind the radio or local TV, or even WiFi today. Radio communication. Yes, it is really far away. Radio waves are actually really good at going far! Radio waves can't go as far on Earth because in order for the waves to get to you, they are going through buildings and even the Earth (due to curvature). That's why you can't connect to a radio station many miles away. But in space, you've got a straight shot all the way to home base with absolutely nothing but air in between. It makes radio communication quite easy, actually.",
"Every time this question comes up, it brings back a favorite memory...I was stationed in Dayton OH, and the local paper ran a letter asserting that space flight was a hoax. \"How can we be getting TV from the Moon,\" he said, \"when I can't even get Toledo on my TV?\"",
"URL_1 wasn't really a clear broadcast. NASA including an erectable antenna on the Lunar Module, but that wasn't the only interesting part of the mission in regards to its live broadcast. You should realize here that a lot of the technology was already in place aboard the LM in order to broadcast information back home. The mission crew at NASA needed to be able to communicate with the crew aboard the LM, they also needed telemetry, voice, and various computer diagnostics to be streamed back to Earth in order to monitor the mission. They used both UHF and VHF streams while they tracked over a C-band beacon on the LM. NASA also developed something called USB (Unified S-band) streaming which combined tracking, telemetry, ranging, command, voice, and television data into a single antenna. You can read all about it on Pop Sci at URL_0 , for all the specs and extra info.",
"Yeah but how bad was the stream delay???",
"Here's a good video discussing how the filmmaking technology of the late 60's wouldn't have been up to the task of making a fake video - it had to be live TV. URL_0",
"Televised broadcast has been commercial since 1930. So by 1960s it's pretty well matured... So why would people think it's not possible?"
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6mvnik | why do some sites need both an address and a ZIP | For example, AT & T and battle for the net need both my address and my ZIP, can't the ZIP be taken from the address? | Technology | explainlikeimfive | {
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"It can...if you entered your address correctly. Both pieces can be used to match each other for verification. You can't verify the address if it's not perfectly entered. And typoing on a zip code is just as common."
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6mycul | How are emails able to be used as evidence in court? Can't someone easily edit them before entering them as evidence? | Technology | explainlikeimfive | {
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"Is there a revealed hash I don't know about to maintain integrity?"
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6mz5kb | difference between seeing/viewing and downloading images | What is the difference to my phone between loading an image so i can see it and downloading an image so i can see it? Besides the fact I have one forever | Technology | explainlikeimfive | {
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"> Besides the fact I have one forever That's it. The viewed image is technically stored temporarily on your phone. While the downloaded one is saved in your storage.",
"Your browser pretty much downloads it to its own \"folder\" if you will and shows you it, when you download it you take that image and it now becomes your possession to move around freely in your own folders. Though technically the image is downloaded in both situations, the shown image may be of lower quality/resolution as a way of quickly displaying it without forcing your browser to \"download\" the full res image"
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6mz614 | How do programmers incentivize self-teaching software? | [Inspiration for this post]( URL_0 ) is this video about Google's DeepMind teaching itself to walk through sensors and "being incentivized to go from point A to point B" which sparked the question, how? | Technology | explainlikeimfive | {
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"Incentivized doesn't really mean anything super-special here. So they've got a neural network that tries things at more or less random. If it works, it keeps the change. But depending on what you're trying to get it learn, it rarely has a simple \"Well that worked' test. So they use \"heuristics\", a guess of how good a change seems to be. Like if you're trying to solve a maze, your distance to the exist might seem like a good heuristic (even though you're down the completely wrong alleyway). \"Incentive\" here just means what they tell the teaching software to keep and what to throw away. But MAN does it make a big difference. You can't just tell a computer \"you are incentive to win chess\". That's a HUGE leap that the search-space just won't make. It's like an inch-worm trying to bridge gaps, it can't reach far. But give it time, it can keep climbing to the top. Ideally you want a clear smooth gradiant from NOT-WORKING to PERFECT-SOLUTION. And any little gain is obvious and apparent. Things like.... making areodynamic plane shapes, the end result is blessedly obvious, you can measure drag. For winning at chess.... a good move is harder to differentiate from a bad move. But you incentive it to take pieces, take territory, protect pieces, and promote pawns. If you reward promoting pawns with +1000 fitness, and only reward taking pieces with +1 through +9, it will try it's damned best to hustle-pawns across the board and disregard the rest of the game."
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6mzoj5 | Why hasn't 720/1080p become Standard Definition, and 4k become High Definition? | Technology | explainlikeimfive | {
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"HD is actually defined as the 720/1080. That's what HD means. It means that resolution. SD means stuff below that, usually 480. 4K means 3840x2160 resolution. Those are just the names for the formats. They don't have a deeper meaning.",
"Terms can't change fluidly because of archiving. In order to preserve things for future generations, they need to know a set of common names and standards to be able to interpret and preserve footage properly. Example: metric is far more common than \"standard\", but if we renamed metric to standard, it would confuse everyone and you wouldn't know which system anyone was referring to"
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6mzz78 | Why software developers use error codes and not just say exactly what is wrong? | Was playing Watch_Dogs 2 and was unable to connect to the servers. Instead of just saying "No internet connection" It says a bunch of gibberish. | Technology | explainlikeimfive | {
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"Error codes report on the specific fault or symptom, not \"what is wrong\". An error code that translates to \"Couldn't connect to server\" for example, means that *for some reason* the program couldn't connect. What exactly is wrong in that scenario? It could be that your internet connection is down, the server is down, both are down, you turned off your wifi antenna, there's a memory leak in the program's net code, the net code is poorly written, and many, many more possibilities. So often, the error will be accompanied by *common* \"what is wrong\" causes of the error code \"Check your internet connection, check your firewall, server busy/try again later, etc.\"",
"Drop a bucket of water and then explain to a cactus exactly what just happened, including the events leading up to you dropping a bucket and what you were thinking about while it happened. Or you could just shrug, say \"error code 346-17\" and move on with your day while the cactus farmer cleans up the mess. An error code is not for the user, its for the developer/programmers. They have a list of codes that mean various things that the end user couldn't do anything with even if they understood the problem.",
"The gibberish is generally helpful to the developers, and usually comes in the form of a 'stack trace'. This is essentially the list of functions the program was working on at the time that the error occurred. There will also be a technical cause for the error, probably due to trying to access an invalid part of memory. If the error comes up enough they can try to catch it and replace the gibberish with something helpful to the user, but that relies on coding a way of catching that particular error, handling it, and recovering the program to a usable state.",
"Two reasons: One, error codes usually aren't intended to be seen by end users. In an ideal world, only a dev will ever see an error code, and the vast majority of their user base have no way to resolve the ones they will see even if they do see them. Two, sometimes the program *can't* tell you what happened, really. Especially in the case of crashes, which are literally cases where a situation has occurred that the program has no code for and thus can't continue. In the case of an 'unable to connect' error, there are so many things that could have gone wrong, and the program isn't necessarily equipped to tell you which one is the culprit. Did your internet go down? At what point? Are the servers too busy? Are the servers down? Did you fail some kind of authentication? It might not actually be able to tell.",
"When you write a program, you add error detection at different locations in your code for all the kinds of things that can potentially go wrong. The error code basically tells the programmer what error detection mechanism was triggered so he knows where to look in his code. These errors are pretty specific and often don't translate 1:1 into something users can make sense of. An explaination for users can (and should) be added though when it makes sense (especially if the user can fix the problem themself, as in your example).",
"Some of this comes from the early days of computers, when they had very limited memory. There wasn't room for full error messages, so a number code was used which people could look up in a reference manual if necessary. That is still somewhat true today when computer programs are built up of many components or modules. These often use a code to pass status (including errors) between them. It is up to the part of the program which tells the user about the error to decode it into a meaningful message, but that may be written by a different person to the rest of the program, and maybe they can't be bothered to provide a message for all the different types of errors which could occur. Or maybe they don't know all the codes which could come back and so they give up and don't bother to decode it. SOURCE: Can program computers",
"An error code can display information much more efficiently than a message that displays the exact problem. So there will be an error code for \"could not connect to the server because of reason x\", one for \"could not connect to the server because of reason y\", and another for \"could not connect to the server because of reason z\". So instead of displaying a detailed description to the user, they'll display a code because it's easier to display in the application and because it's faster to determine exactly what's happening if you're already familiar with the error code",
"Just to add to the other very good examples, some error codes can be made automatically-self-generating in the code or by the compiler, for example a programmer could write a single simple routine called \"print_error\" and call it 100 or 1000 times from all different spots in the program and get a useful (to them) error code every time in an easy-to-read format. That routine could automatically grab some info, that is either compiled in (things called \"preprocessor macros\" can insert things like the name of the file, the name of the function you were inside, the line number of the source code where the call happens, the date / time the file or program was compiled, etc.) or worked out on-the-fly - for example the name of a file you couldn't find, some bit of data you were looking at, etc. Another reason for \"meaningless\" (to the end user) codes is that it gives some degree of security and indeed hides embarrassing f**kups from end users."
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6n1fdq | is it possible to make it so an ISP can't throttle your network speeds? If so, how? Just preparing for the apocalypse... | Technology | explainlikeimfive | {
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"Yes and no. If you're using end-to-end encryption, they can't tell what you're communicating, but they might just throttle you just because they can't tell. With end to **end** encryption, they can also tell where your endpoint is. Accessing Netflix over HTTPS, they still know that Netflix owns the IP Address you're communicating to. You can instead use a tunnel endpoint that reaches out from there, but then you risk the ISP for *that* endpoint throttling your data. On top of all this, they can also infer what you're doing based on traffic patterns. If you make an initially reasonable sized request, followed by data coming in at a fairly consistent rate, they can infer that you're using some sort of streaming service. Also consider this: The model that Ajit 'Dear god I hope he spills his entire stupid oversized mug of hot coffee all over his crotch' Pai is trying to get passed allows for \"Fast Lane\" traffic if it's paid for. Without building explicitly new infrastructure, this means that the default is the slow lane, and certain services pay for \"fast lane\". Thus, they throttle ALL traffic unless they can explicitly identify it AS a fast-lane service. (Keep in mind, that all they're doing to create a fast lane is slow down everything else and use the existing infrastructure as a fast lane).",
"Your ISP is controlling all traffic coming too and from your computer so they can decide which packets to forward and which to drop. However it does sound like you are misinterpreting the concept of Internet neutrality. It is not about throttling your bandwidth, ISPs have been doing that since before the Internet and it is the core of their business model. However the problem is that they would like to treat different traffic differently. Imagine for example that Comcast made a deal with imgur so that traffic to their servers were not throttled the same way. That would be unfair to reddit or any startup image hosting sites. And if the end users got mad about it then Comcast might give them the option to upgrade their plans to get around the restriction. And what if a Verizon have a plan that gives you free access to Facebook, Twitter and the services owned by those companies. How would Google react to that since they have competing services for all of them. And what about the hundreds of attempts at starting competing services. And what if Google Fiber would start changing the content of the web sites you visit to include advertisement. There is a sort of way to get around this. Your ISP can only act on traffic it knows what is. So what you can do is to make sure that the traffic is encrypted and sent through a third party. This is why there are so many VPN providers. The only thing the ISP see is that you are sending a lot of traffic to and from a VPN provider. It does not know who the final destination is or what the content of the traffic is. Another useful tool is TOR which is sending traffic though a network of relays around the world maintained by enthusiasts. The simplest way to use it is to try out the TOR Browser Bundle which is TOR, firefox and several addons to improve privacy.",
"There are other answers that have touched on this in an abstract way, but haven't offered a concrete solution. Yes, you can (possibly) by using a VPN (Virtual Private Network). VPNs are \"tunnels\" through the internet that allow you to connect to server outside of your ISP with which all the communication is encrypted, that server then connects to the websites/services for you on connections that may or may not be encrypted. As long as the ISP doesn't throttle the connection to the VPN (which might happen for popular VPN services) you can connect to any website without fear of your service being slowed down. edit: It is likely that ISPs will throttle connections to popular VPN services, but it is possible to set up your own."
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6n4h5f | Why does it take a computer a bit of time to shut down? What else does it have to do before it cuts power? | Technology | explainlikeimfive | {
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"First the operating system sends signals to all the running programs telling them to close. This gives them time to gracefully close. That means saving data, closing file handles and cleaning up. The operating system waits for the programs to close. After a short while it gives up and shoots them in the head, any data they had in memory is lost. Then the OS does the same thing itself. You can see this in action, open notepad and type some stuff then shutdown the computer. Windows signals notepad to close but notepad reacts by asking you if you want to save and waits for a response, meanwhile the shutdown is blocked. After a while windows just kills notepad."
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6n5s9e | How do electronic key cards for hotels and college dormitories work? How do the card readers know to reject cards not associated with a room or building? | Edit for clarification: I'm referring to the "tap" or insert cards that do not require you to also input a code. Thanks for reading! | Technology | explainlikeimfive | {
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"Because they're programmed to. If the door code is 12345, then a card coded 24555 isn't going to open the door."
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6n64wz | [Technology] Does being in wifi versus using data affect battery drainage? | Technology | explainlikeimfive | {
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"Wifi uses less battery. It has to do with signal strength. When using cellular data, your phone has to transmit a higher strength signal because the cell towers tend to be much farther away. Assuming the wifi is nearby, the signal is going to be much stronger, and take less energy to transmit and pick up."
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6n8ezt | Why is a photocopying machine so huge compared to a normal colour printer? | Technology | explainlikeimfive | {
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"There are very small photocopiers too. On the large ones, most of the extra size is for complex paper handling: several large supplies of different sizes of paper; a collator that can make 10-20 separate copies of a whole document; sometimes an auto-stapler; a high-speed jam-resistant paper feeding and duplexing mechanism.",
"It is not necessarily bigger. You can get photocopier that fits in your bag and you can get printers that take up the room. But even the big photocopier have a modest sized printer and a modest sized scanner. Most of the space is taken up by rollers and shelves for moving and manipulating the paper. And this part is optional. But there is a tendency that on smaller printers you omit the scanner part to make it more compact but for bigger printers you have the scanner module as it does not matter that much and is quite useful. So it is not so much that photocopiers tend to be bigger then printers but more the fact that big printers tend to be photocopiers.",
"You see photocopiers in office environments. They are required to handle a larger load of workflow so require more storage, and other functionalities like scanning. Your average home printer is small because it needs to take up less room to fit in your computer room at home and it doesn't get used for 10 hours every day.",
"8 1/2x5 paper limits how much smaller you can make them without paper storage capacity being unacceptably small.",
"Besides the extra paper trays and paper handling mechanism, there is also the design constraint of wanting a unit the can be put on the floor, but is tall enough to be used by a standing person.",
"Normally they are not it's the paper trays and feeds under that make it look bigger than it actually is. But for example in the office I'm in the copier is bigger as it, a Xerox workcentre 7428, is designed to print a lot of pages quickly. But even then most of it is taken up with the large laser toner cartridges"
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6n8yo2 | If programming is mainly a bunch of math and numbers then how is a video game created? | I have learned some programming in the past but I cannot figure out how you build a game from it. You need some graphics and sounds for it too (which are tasks for graphics designers and sound engineers) , but I don't know how do you integrate that in your programming (math/ numbers) and in the final product, the game itself. How is it all mixed together to provide what we finally can play? If you know the answer, please write down the original names of what you are describing (like assets) even if you explain what it is. | Technology | explainlikeimfive | {
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"So programming isn't really \"a bunch of math and numbers\". A better way to describe it is \"a bunch of instructions and decisions\". Math and numbers are used, but programming at it's core is telling the computer to do certain things, and making decisions. So let's look at the simplest example of a real computer game. [Pong]( URL_0 ). You need a few things for pong. * the \"paddles\" to draw * the \"ball\" to draw * Numbers to write, for the score * The logic to make it work. So if you were making this game, normally what you'd do is do something called a \"game loop\". A game loop is a way to designing a game where the same chunks of code are ran over and over again. This code at the simplest might be set up like this, written in C#, a programming language: void GameLoop() { while (gameRunning) { GetUserInput(); UpdateEverything(); DrawEverything(); } } What this is saying is, when you run GameLoop() get the user's input, update everything, and then draw everything. If \"gameRunning\" turns out to be false, get out of there (and the game will end). So what do those steps do? void GetUserInput() { KeysPressed = GetPressedKeys(); if (KeysPressed.Contains(Key.W)) { Player1.Position.Y = Player1.Position.Y - 1 } else if (KeysPressed.Contains(Key.S)) { Player1.Position.Y = Player1.Position.Y + 1 } if (KeysPressed.Contains(Key.Up)) { Player2.Position.Y = Player2.Position.Y - 1 } else if (KeysPressed.Contains(Key.Down)) { Player2.Position.Y = Player2.Position.Y + 1 } if (KeysPressed.Contains(Key.Esc)) { gameRunning = false; } } This says, first, find out what keys are pressed (I won't cover how this is done, but imagine what ends up here is a list of what keys are pressed right now). Now, take that list, and if it contains the 'W' key, chang the position of the first player on the vertical axis (Y axis) and decrease it. Since the top of the screen is always zero, this says move Player1 up. If you press S, move player 1 down. If you press the up arrow, move player 2 up, if you press the down arrow, move player 2 down. If you hit Esc, the game will quit when it starts the next frame void UpdateEverything() { HandleBallBouncingOffWalls() HandleBallBouncingOffPaddles() if (Ball.MovingUp) { Ball.Position.Y = Bally.Position.Y - 1; } else { Ball.Position.Y = Bally.Position.Y + 1; } if (Ball.MovingLeft) { Ball.Position.X = Bally.Position.X - 1; } else { Ball.Position.X = Bally.Position.X + 1; } if (Ball.X < 0) { Player2.Score = Player2.Score + 1; Ball.X = Screen.Width / 2 Ball.Y = Screen.Height / 2 } if (Ball.X > Screen.Width) { Player1.Score = Player1.Score + 1; Ball.X = Screen.Width / 2 Ball.Y = Screen.Height / 2 } } First, we have to HandleBallBouncingOffWalls, which is a separate bit of code (a method) which determines if the ball hit the top or bottom wall, and changes its vertical direction. I won't cover that here right now. The same thing is done with HandleBallBouncingOffPaddles, but for horizontal movement. Next we use that movement, if the ball is moving up, we change it's position upwards (same as before), otherwise we move it down. If the ball is moving left we shift it left, otherwise right. Finally we need to determine if a player scored. We do this by figuring out if the ball crossed the left or the right edges of the screen. If so we put it back in the middle of the screen. The key here is that **nothing has actually changed on the screen**. All we did is changed the values we have stored for our objects. The screen is still showing what we drew last time through (the previous \"frame\"). Now we draw stuff. void DrawEverything() { DrawRectangle(Player1.Position.X - Player1.Width / 2, Player1.Position.Y - Player1.Height / 2, Player1.Width, Player1.Height, Color.Red); DrawRectangle(Player2.Position.X - Player2.Width / 2, Player2.Position.Y - Player2.Height / 2, Player2.Width, Player2.Height, Color.Blue); DrawRectangle(Ball.Position.X - Ball.Width / 2, Ball.Position.Y - Ball.Height / 2, Ball.Width, Ball.Height, Color.White); DrawText(Player1.Score, 0, 0) DrawText(Player2.Score, 400,0) } The first three lines are basically the same, they say, first, find the top left corner of this thing (it's center X, minus half it's width, and it's center Y, minus half it's height), and make a rectangle from that point down and to the right. That rectangle will have a width of the size of the object, and a height of the size of the object. We'll also tell it what color to draw. The actual DrawRectangle call is normally something very easy to do in a programming language, but I won't cover it here. DrawText will write out text on the screen, I also won't cover how it works. But in this case we just pass it the text we want to write (the score), and the x and y positions we want to write it. Now there are MANY things that are glossed over here. But this is **generally** how a very simple game would function. Finishing this up and making a working game would take 10 minutes or so, even if it would have flaws. Let me know if you have any questions or want me to follow up on anything in particular. Specially I glossed over: * Creating the objects (initialization) * Reading the keys * Collisions detection (walls/paddles) and response * Actually Drawing shapes/text PONG!",
"Former game developer here, The math you want to learn is Linear Algebra. A \"vector\" indicates a point, or direction and magnitude. For video games, it'll typically have 2-4 components of X, Y, Z, and W, in that order. Vectors have lots of ambiguous names, because programmers tend to overload and abuse the terms. Mostly the name is specific to the context. The same data structure tends to be used to represent a point or a direction and magnitude. If your language has strong typing, you can make multiple types with essentially the same properties, but then you would have to be particularly mindful of when you can and can't mix types to keep your math correct. A \"matrix\", in essence, describes the different planes of your vector space and how they relate to one another. They typically have 2, 3, or 4 component vectors of the same names as above, for video game purposes. These literally describe the shape of a space, a universe if you will, and every model in your game will have one. So every joint of your player model, for example, and they'll be stored in a hierarchy. These things describe rotation, translation, scale, and various skews. So every model exists in \"model space\" - a modeler will make, say, the hand of your player in an editor, and it will be centered about the origin (coordinates 0, 0, 0) of 3D space in the editor. You then have a hierarchy of the player character body parts, the torso tends to be the root, and then you have the shoulder, the forearm, and finally the hand. Each element in the hierarchy has it's own matrix, so you multiply the hand matrix against the torso, the upper arm, and the forearm matrix to finally get it rotated and translated into place. You always multiply down the hierarchy, so if the player character moves or rotates, that root matrix, of the torso, gets changed, then all children matrices all have to be updated as well. The root of any model hierarchy will be a leaf relative to some other hierarchy, say a room, a building, a map quadrant, ultimately to the world origin. Now your model is in \"world space\". There's one final matrix to multiply against, and that's the camera. The camera is mostly just a matrix, but the numbers represent a \"projection\". Like I said, a matrix describes the planes of space and how they relate to one another. What you can do is collapse the Z axis and bend the X and Y axes so you get a \"perspective\", where things further away look smaller, and everything converged on the horizon. This is how we go from 3D space to 2D space. The rest of the camera is a frustum, a 3D shape of a pyramid with the point on the top chopped off. This is for culling - anything outside the frustum isn't in view, either too far off to the sides or too far away. This camera is essentially just a matrix, and all this work is to take all the 3D points of the model and multiply them against this matrix, going UP the hierarchy, so we know how each point projects onto a 2D space that is your screen. These points are then mapped to pixel coordinates. After that, there are \"space filling algorithms\" to take points and make triangles by coloring pixels within the edges that form the triangles. But typically we don't even do that. Textures use a UV coordinate system (a separate 2D vector space) that maps a texture to a models surface. Add some LA math, and you can map texture coordinates onto the screen. LA is just math, it's not like it's specific to video games - it's used in physics and anywhere a system of linear equations make sense. Google Pagerank? LA, it's just a big matrix, though it doesn't represent 3D space. So you can get mired in the abstract principles of LA if you want, and you'll be better for it, or you can study LA specifically in the context of video games, and that should get you going. Check out URL_0 and Gamasutra for great sources and tutorials. There's also a gamedev sub to look into. Game engines take care of a lot of this for you, whether it's a 2D game or 3D, this is how they all do it. As for assets, 3D model programs have these gigantic project files. Games don't use these files, they contain shit like the editor's undo stack. Useless to us. Those models are exported into file formats that really break the data down to it's most basic components, a list of all the points, a list of sets of 3 indexes into the list of points to describe the triangles, file paths to the texture files, and UV coordinates. If it's a composite model, it'll have some matrices in there, too, and if you get really fancy, maybe game specific stuff like animation sequences. Some of these formats are text, some are binary, some are open sourced and generic, some are proprietary, some are merely specific to a particular game engine, like Unity. If you want to write out and read in Unity files for your game, kudos to you, but you don't have to. Some editors come bundled with exporters for well known formats and engines, some engines come bundled with exporters for well known editors. Textures are always in a lossless format, so BMP or PNG, for example, and never JPG. Disk space is cheap."
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6naq9h | Will placing the Internet under Title II allow it to be censored like radio or will it allow the internet to continue to stay open and free? | Technology | explainlikeimfive | {
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"Private telephone conversations are covered under Title II, and there's no censorship of telephone calls. In practice, censoring the Internet isn't directly possible. You can make a separate net, not the Internet, which you censor. China, for example, does this. There is no Internet in China, only \"China-net\". If someone is telling you Tittle II will censor the Internet, they are trying to turn you against regulated net neutrality. These are considered \"bad people\" around here, as Reddit's an advocate for net neutrality (so that you can get to Reddit)."
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6nbe59 | Why did so many cavalries use curved swords (sabers, scimitars, etc)? What advantage do they give? | Technology | explainlikeimfive | {
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"A generic straight sword is good at both stabbing and slashing, can be used two handed for extra power, and can be used against opponents on either side of you. On a horse, you are basically just slashing, one handed, to one side. A curved sword is better at slashing, at the expense of stabbing and being useful in both directions, but those are less important on a horse.",
"If you stab someone with a sword while galloping on horseback, you ain't getting that sword back unless you're strong enough to lift an armoured man one-handed. Better to eviscerate him with a slash.",
"Curved swords make it easier to slice as the horse runs by a target without losing your sword in the target.",
"The blade allowed a slashing cut without getting stuck in the body. The shape also allowed it to take an impact. Instead of the taking all of the energy in one spot it would allow it to travel the curve. At least that's my understanding of the mechanics.",
"If you stab somebody while on horseback there is a fair chance that the blade will get stuck in bone or whatever and you'll end up losing it or falling off of your horse. Both of which will get you dead. But if you're just slashing then it most likely isn't going to get stuck in any fleshy bits. Curved swords are superior slashers vs straight swords. So it makes sense to use a curved sword and go for slashes.",
"Curved blades slice better because you end up with more surface area sliding along as it moves diagonally. Straight swords are more of a chopping motion, applying the force/cut directly at the point of impact and only really sliding so much. However, as a curved blade \"chops\" downwards/sideways the natural motion of the movement slides the blade along it's length more than it straight chops. Think of a saw vs an axe and you get the idea."
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6nf8i2 | How can a video filmed 50 years ago, not in HD, then be rereleased in HD? | Technology | explainlikeimfive | {
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"text": [
"35mm film actually have much high resolution than digital HD. Typical HD is 1920x1080 which is 2,073,600 pixels or about 2 megapixels. 4K UHD is 3840x2160 which is 8,294,400 pixels or about 8 megapixels. 35mm film has about 20 megapixel resolution. If the original film are well preserved they can go into a machine to be scanned and converted to HD or UHD without a problem. Question is who will pay for it and is it worth the effort. URL_0",
"In the past, we used celluloid (or physical film) to record the visual part of film. If such a roll of film is digitalized, it's not a matter of resolution of the film, which is dependent on the density of the light sensitive material used, but it becomes a matter of the digital sensor it is projected upon. Since HD is the standard, it will be recorded as such. In the Netherlands, the museum for film in Amsterdam is digitalizing a lot of celluloid even goes as far as using a 4k or 8k digital sensor, to get the highest possible resolution out of it."
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"https://www.howtogeek.com/199182/ask-htg-how-can-studios-release-high-definition-versions-of-decades-old-movies-and-tv-shows/"
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6nff2j | What are AVX (Advanced Vector Extensions) for? | Technology | explainlikeimfive | {
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"text": [
"For speeding up calculations. Vector Extensions are special CPU instructions which can operate on a larger number of bits than the CPU typically does. Alternatively they can be used to do multiple operations at the same time if the values are a smaller number of bits. For example, instead of multiplying numbers one at a time, vector instructions can do several multiplications in one go. SSE is 128 bit. So it could do 4 * 32 bit calculations with a single instruction. AVX is 256 or 512 bit (depending on the version). So in theory you can do 8/16 calculations in a single instruction."
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6nftrw | how come portable hard drives haven't advanced beyond 1 Tb/ 2Tb size these last 5 years | Technology | explainlikeimfive | {
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"Have you even looked for one? I bought a 4Tb hdd for about £90 nearly a year ago URL_1 I'm sure you can even get 8tb if you want to splash out. URL_0",
"There was a big increase in capacity some years ago with perpendicular recording: URL_1 But this has kind of reached maturity. You can't make the platters physically bigger, you can't squeeze in more than so many platters. Improvements are more incremental. They are still being made, but at a slower rate. The next thing after perpendicular recording is shingled recording, but it's less of an improvement. edit: in case anyone doubts this, here's Seagate themselves saying that they have reached the limit: URL_0",
"There's plenty of demand in the 1.8\" and 2.5\" form factors for dense drives, but they don't come from consumers. A 2 TB drive is going to hold the backup of a normal family's entire digital life - music, movies etc. When you combine this with the increased use of streaming services (we don't even use MP3's anymore - we're a spotify family, and our digital movie library is still growing, but with Netflix and Amazon, it's not growing as fast), there's just not much need for any one person to have more than a couple terabytes of data. There are exceptions, but they tend to be either hobbyists or professionals in areas that leave a heavy digital footprint. Now, those 2.5\" drives have demand, but they are in the business sector, where companies will string them together into an \"array\" and make them look like a single large disk or many smaller disks, adding features that prevent data loss if one or more of the hard drives fail. Eventually the spinning disks will go away. Flash drive technologies are getting more dense than the spinning platter drives at the same price point, and are cheaper to operate (because there are no moving parts and do not consume much power when unused). Short answer, although you will see drive densities in the 8-10 TB range, I would not generally expect them to be marketed to consumers (although you can find and use them if you want). Consumers will be increasingly marketed flash drives and SSDs. Source: work in IT industry."
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"https://www.amazon.co.uk/Verbatim-47687-3-5-Inch-Store-Desktop/dp/B01NBCJPQL/ref=sr_1_25?s=computers&ie=UTF8&qid=1500124315&sr=1-25&keywords=8tb+external+hard+drive",
"https://www.amazon.co.uk/Samsung-Slimline-Portable-Hard-Drive/dp/B00ZQXP3Q2"
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"https://www.youtube.com/watch?v=xb_PyKuI7II"
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6ng0un | Why do we have to limit clock speed on processors? | Technology | explainlikeimfive | {
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"One problem is that circuits are really analog, even if we can normally treat them as digital. If you take something like an AND gate, we can normally just assume that its output will be on when both inputs are on, and off otherwise. But when the inputs change, it actually takes some fraction of a second for the output to switch to match the inputs. You can think of the clock as providing a delay after each change to let everything stabilise in the new state. At some point, the speed of light becomes the limiting factor, since changes can't propagate across the chip any faster than that. With a 1THz clock, there's only 1 picosecond between ticks, and no signal can travel further than 0.3mm in that time. If your CPU is 40mm across, that's going to be a big problem.",
"Other than the increasing energy bill and the exponential additional heat being pumped into the system that needs cooling? There are gate delays, there is a small delay between a gate is used before it can be used again that serves as an upper ceiling. There is the extra power being spent. As you increase the clock speed you increase the power needed to run said chip. a 1thz processor is going to spend a lot of power for a common consumer. There is the big killer: Heating. The heat generated by the chip with extra clock speed will grow faster than you can hope to cool it as a consumer. You'll have a 1thz processor for all of 30 seconds before your computer shuts down to protect itself from overheating. If you want a supercomputer it's much smarter to just link together many computers and have each share a load in the computation. It costs more energy, but it's more heat-friendly and easier to set up.",
"To get higher than say 5-6ghz would require the electron to travel faster than the speed of light. The solution to this is to shrink the cpu die smaller and smaller, but this causes another problem; When there's not enough material separate each logic gate, you have electrons hopping over and producing inconsistent output, an undesirable result in a cpu. /e spelling"
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6ngtjv | Why do automatic toilets and urinals flush while I'm still very clearly using them? | Like, stop rushing me, man. | Technology | explainlikeimfive | {
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"text": [
"Tear off some toilet paper and drape it over the sensor. If you know you're gonna drop a deuce, get some wet paper towel first and use that to drape over the sensor. I've been doing this for years adverting the awkward mist-splash.",
"The sensors are built to detect an increase in distance to the nearest object. If you lean in close, and then lean back, it will think you left the stall and will flush. The other possibility is that the sensitivity is set too high.",
"There are different types of automatic urinals and toilets. In well used areas they have timers and go off at regular intervals. However the most common have sensors that detect if you are there, either a PIR sensor (infrared) or a laser. However if you move around a bit the sensor might think that you are done."
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6nh3ot | What is the difference between having stream saver on and off for AT & T? | Technology | explainlikeimfive | {
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"text": [
"It limits the quality of video streaming while simultaneously limiting the use of data. Basically you could watch 1 hour of HD video on your phone for about a gb, or you could watch that same hour of video at a lower quality for half a gig or less. Basically boils down to if you have unlimited data, fuck that shit turn stream saver off. If you have a finite data plan, then it's great because you can stream more for less. Hopefully, that helps out."
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6nhsqe | How did people come up with names for all the HTML colour codes? | Such as “Lightsalmon” (#FA07A), “Lemonchiffon” (#FFFACD), “Papayawhip” (#FEFD5) or “Goldenrod” (#DAA520) etc.? | Technology | explainlikeimfive | {
"a_id": [
"dk9kvmy",
"dk9jzco"
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"text": [
"[This article at ArsTechnica]( URL_0 ) says that the early \"colorful\" names were taken from the Sinclair Paints catalogue.",
"Wikipedia lists some history at their articles for [web colors]( URL_1 ) and [X11 colors]( URL_0 ). Most of the web colors are derived from the X11 colors -- there are a few differences, but it is pretty close. As a first pass, they just implemented the primary colors in the RGB color wheel. Then over time there was demand for the colors in between and paint colors they're more memorable have interesting names. The X11 colors date from the mid-80s so there was a lot of time for those to get generated."
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"https://en.wikipedia.org/wiki/Web_colors"
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6nidv3 | What's the difference between a radio transmitter antenna and a radio receiver antenna? | are they both solenoids or metal sticks? | Technology | explainlikeimfive | {
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"text": [
"There is none. \"It is a fundamental property of antennas that the electrical characteristics of an antenna, such as gain, radiation pattern, impedance, bandwidth, resonant frequency and polarization, are the same whether the antenna is transmitting or receiving.\" So, if you take an antenna and modify it to be a better transmitter with a higher gain, it is also a better receiver. If you take an antenna and make it transmit directionally, it also receives directionally. If it transmits a specific frequency better than others, it receives that frequency better than others. For that reason, normally they're just called antennas, without reference to whether they are for receiving or transmitting."
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6nndlo | How do cellular providers give consistent bandwidth to multiple users at one time while my wireless router gets slowed down with multiple users? | Technology | explainlikeimfive | {
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"text": [
"Your router has a set amount of bandwidth that it is getting from your internet provider, and a set amount of bandwidth the users on your end of the router can have in total. Imagine you're distributing water. The pipe coming into your house is coming in at 10 liters per second. If you have 3 people in your house, and they're all asking for 15 liters per second, none of them are going to get what they want. Without other configurations, the requests will be balanced out to use up the 10L/Sec. Cellular providers have a lot more than 10L/Sec to give, and they set limits on what each person is allowed to get. At home, you can set Quality of Service limits on specific devices to put a ceiling on how much bandwidth they can use.",
"Actually they don't. Their towers have a total bandwidth limit just like your router. That's why service is sometimes slow at very crowded events, like sports games or rock festivals."
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6nozyu | Why can't you rename a Windows file with some characters like :, etc.. ? | :, maybe can be used but i am not now on my PC to check what characters can't be used so sorry if I am wrong but that was just like an example, I think you get what I want to say. | Technology | explainlikeimfive | {
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"Certain characters are reserved because they have other meanings. The colon (:) means the name preceding it is a device, such as a drive (C:) or a port (COM1:). Others are wildcards, like asterisk (*) or query (?). Plus (+) is used to concatenate files together. The backslash (\\\\) is a path separator. Double-period (..) is an alias for the parent directory. Angle brackets ( < > ) are used to pipe output from/to a file or device.",
"It's buried deep in the DOS file name handling basis of Windows that some characters are \"reserved\" to have significant meanings in commands. ? and \\* for wildcards in file operations, / and : for command option switches, \\\\ for directory separators etc. It could have been completely rewritten at some stage to get round the limitation but then may have backward compatability issues. List of forbidden characters - \\\\\\/:\\*?\" < \\ > |"
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6np4s8 | How do foaming soap dispensers work and how do they change liquid soap to foam? | Technology | explainlikeimfive | {
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"dkb4mgh"
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"text": [
"They have little grids on them that they force soap through that 'aerates' the soap by allowing air into the grid. You can get the same thing on a sink faucet that makes the water bubbley as it comes out."
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6nq6da | How negatives of images seem to have so little of color variation, but the normal versions of images can have plenty | Technology | explainlikeimfive | {
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"dkbw5gn"
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"text": [
"If you consider real analogue negatives, you need to look at them at just the right light conditions to get good contrast levels, just like the image produced by them will get low contrast if you either over- or under-expose when making the positive photo. Also, our eyes have evolved to see the common colors the best, if you flip them the stronger contrasts are no longer in the colors we see the best. But if you take a picture of a negative, the negative of that should have stronger colors ;)"
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6nqzzc | How do other people slow down my connection speed? | I live in a very rural area (an hour away from city) so my internet is really slow. I know when other people in the area are not online (like when they are at work or outside) the internet is much faster, reaching 3-4 Mb/s. But when everyone comes online it runs at a snails pace, dipping down to 500 or even 50 Kb/s. Why is it that the other customers on the service slow it down so much and why does it slow down so much? | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"Imagine a water pipe. If you're the only person using it you get full pressure. The more connections to that pipe the weaker the pressure.",
"The local service connection's bandwidth is being used up, when you have access to it at low use times you get faster connections, but when you as everybody else are online you only get connections based on your service priority, and thus you get slower connection speeds from the system, if somebody comes on with a higher priority connection from their subscription you will receive a lower priority connection rate."
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6nrrpd | Is it easier to make a movie with a cgi "invisible" monster, or a visible practical effects monster? | Technology | explainlikeimfive | {
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"Low-budget CGI will likely result in a worse film than low-budget practical FX. Both can work, but practical FX can be bodged up more easily by a bunch of amateurs and (this is the clincher) if you can do stuff in-camera on-set the actors can see & react to it better (more believably). This is one of the main reasons big studios are going back to practical FX for a lot of things (source: a friend works in the industry). CGI is great and still used heavily for touching up, hiding wires and stuff, filling in backgrounds and all that it excels at, but if you want your actors to have a believable reaction to a monster you can't beat a real monster really coming at them on-set, even if it's a dude in a costume and you CGI in the glowing red eyes and paint out the zipper up the back later in a computer. There are decades of brilliant practical FX experience out there, much of it was done very cheaply (or would be very cheap nowadays with tech like 3D printing), you can find loads of documentaries & behind-the-scenes stuff on YouTube and blogs etc. - the guys from Mythbusters did a lot of effects work and you see them showing a lot of techniques in the programmes & their later work on Youtube. Also a lot can be achieved with creative shooting - some great movies you don't see nearly as much as you think you did: Jurassic park they used a lot of reaction shots and practical effects like the glass of water to make (by modern standards) pretty poor CGI seem more believable. Attack The Block is a favourite example - the monsters are pitch black which makes the effect very cheap as you just have to make a black blob with two glowing eyes rather than a full detailed believable monster. A lot of the old film techniques are very achievable with modern digital editing etc. for almost zero cost."
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6ns0p8 | How does Instant Messaging differ from e-mail? | Technology | explainlikeimfive | {
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"E-mail works in a similar way to the post office. You write a message and hit send, it gets passed off and the address read to see where it goes. It gets sent to that location where the address gets read and sorted into the correct mail box. Multiple clients and multiple servers all over the world just like mail boxes and post offices. Instant messaging is multiple clients and one server. Think of it like inter office mail. Everyone gives their letters to Charlie in the mailroom and he brings it up to their office. Charlie already knows where Carol is, so he can bring her a letter quickly. If who you want to talk to doesnt work in your building, Charlie can't deliver a message.",
"AOL Instant Messenger (AIM), MSN Messenger, Yahoo! Messenger, IRC (and probably ICQ) are all real-time instant messengers. With the advent of text messaging you don't really see them much anymore outside of offices. It's really just computer to computer messaging through a variety of platforms. There were third party programs like Trillian and Pidgen that could manage them all through one interface. I LOVED Trillian. It was a real status symbol back in the day if you were a kid who could stay logged in to all of your messengers 24/7. edit: I tried to ELH5."
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6ns4h6 | teaching/learning robots | How much groundwork programming does it take to let a robot know that "stand up" shouldn't look like a topsy-turvy turtle? Is it like: these are the rules, now bring it to a usable order? How does the robot know what makes an order usable? | Technology | explainlikeimfive | {
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"imagine you have some inputs (sensors, energy), some internal nodes (stuff that can be connected together), some outputs (motors) and a simple test to \"score\" the result, f.e. how close you are to the desired result. now a computer connects everything randomly, and uses it as start state. now it keeps repeating 2 things 1) scoring; check how close we are 2)random changes and scoring again; if we got somehow better, use that as new start state... and repeat that until you are within an \"error margin\", aka, your are close enough to the target. this can take a few cycles or billions, it depends on how you choose inputs/nodes/outputs, how you \"randomly change\" stuff (what changes how much?) and how good your score function is. tl;dr: learning here is just \"random\" trial & error until you are within a defined goal setting, the pro is also the con, in that you dont need to or can know \"how\" it solves the problem, just how reliable (test alot)"
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6ntn59 | How does streaming work that allows millions of discrete viewers to stream a popular show? | For instance, when Game of Thrones season 7 premier debuted on HBO GO/Now, how do the servers handle the flux of viewers? Do the servers need to supply a copy of the file to each viewer? | Technology | explainlikeimfive | {
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"It is possible to stream to multiple devices via [IP multicast]( URL_1 ) - the network then copies at each step. However, due to compatibility, billing and security reasons, IP multicast is not available on the general Internet. Another alternative is using a peer-to-peer network, with the central servers being part of the network and/or allowing conventional downloads on top of it. For instance, Windows update uses this, but also illegal torrents, like those listed by The Pirate Bay. Since mobile apps or web browsers run only while the user is watching the video and many users have restricted or metered upstream capacity, it is not as feasible for HBO. So what HBO or their technical provider does is indeed simply have a lot of servers. Each server stores a copy of the most-requested videos - that's called *caching*. For every device, the server sets up an encrypted connection, encrypts/obfuscates the video so that it's harder to extract as a file (this is called Digital Rights Management, DRM) and sends it to the clients. Compared to other tasks like video recoding, database aggregation, or searches, this is quite easy work for a computer. A 10GBit/s server can serve 2000 users at once, while being about as powerful as a good gaming PC, although of course with a different focus - these servers will have lots of RAM and use graphic cards only for encryption, if at all. HBO does not need to buy thousands at servers just for the premiere; they can adapt to the demand by renting servers for a couple of hours, using services like [Amazon EC2]( URL_0 )."
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6nwefw | Why is running a game (or anything) in Windowed mode more stressful on a computer than running it in Fullscreen? | I've noticed this myself when playing GTA, I was running the game at half the framerate while running it in windowed (borderless) than when I switched over to fullscreen. | Technology | explainlikeimfive | {
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"When you are windowed, Windows not only has to draw your game screen, but all of the other things running in windows too. Plus, it has to convert the resolution you have chosen to something smaller. When you run in fullscreen mode, All of the graphics power is reserved for the game alone, and no conversion needs to be done.",
"To add to what has already been answered, the operating system whether it is Windows, OSX, Linux based, or otherwise, has other programs it has to keep running in order to maintain a working system. Some of those programs can be suspended (paused) and moved from main memory and stored on the hard drive's cache file when a full screen application takes over. Thus it gives more CPU and memory to the full screen program.",
"When you are in fullscreen mode, Windows knows it doesn't have to do anything else, and can give mostly give the screen over to the game to control directly. That is what DirectX is all about. When the game is windowed, it doesn't get that kind of control, and even if it is the only thing doing much, control is reduced."
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6nwimm | How do the detectors at Walmart or other stores work? | My coworker and I were having a discussion about working at Walmart and dealing with the self checkout machines. We came to a point where we wondered, "If you didn't scan all your items and tried to go through the detectors, how would they know to go off?" Is it an infrared thing? How could it be possible? Edit: By "detectors," I mean the ones by the doors as you are leaving the store. They sound an alarm of some sort if you have something that hasn't been scanned and paid for despite the fact that the items don't have any sort of beacons or tags on them other than the barcodes. | Technology | explainlikeimfive | {
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"The detectors don't detect everything, they just detect security devices inside certain products. You'd need a magnet to remove them. If you're in the self checkout, the red light will turn on, and an employee will come remove the security tag. If you stole something like a candy bar, it wouldn't set off the alarms at the door. Most things wouldn't really, they're there for show more than anything else.",
"It is very possible. At a certain point when I was younger I had a bit of a shoplifting habit. I won't lie and say I needed to steal because it was totally just a self destructive habit I did for the rush. But yeah, self checkout was great. I would just have a full cart, and bag everything and click that it was going in the cart. Then I would put these bagged items in the cart over the stuff I was taking. Finish checking out like normal and walk out. Take $80 worth of stuff and pay $25. For the most part the only security is in the form of magnetic tags or strips. Little white things that contain a magnet. The sensors at the doors can detect them and they go off when one is passing through. The magnets are deactivated when you swipe them across the register, near the warning labels to keep cards away. Some magnetic locks have needles for attaching to clothes, or wires for wrapping around electronics. When I worked at Fred Meyer, you were supposed to respond to one of the sensors going off, if you weren't busy. If you did, you found what item was causing the problem, check the receipt, record it on a log, and they gave you $1 every time something was logged. It was super dull. Nobody really cared to do it. We would prank each other by taking the little tags and putting them in people's clothing or hiding them on carts so the cart always set them off.",
"great watch about this topic - magnetostriction URL_0 basically the little metal strips inside those white anti-theft tags are made to a precise size and thickness that slightly alters the magnetic 'signal' being sent out from the detectors. a lot of products nowadays that are worth a shit are actually built with those little strips on the inside like power tools and stuff like that."
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6nwum8 | How do "framerates" make a difference in videos? | I saw [this post]( URL_0 ) ("Framerate synced with wings") I don't know anything about photography or science so this might be a stupid queston, but what does "syncing framerates" mean and how does it make that bird look like it's not flapping its wings? | Technology | explainlikeimfive | {
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"simplifying u/Ging1721 's answer, Got a slow blinking light? even a car's indicator will do now start it and blink your eyes in such a way that when you open them it seems like the light isn't actually blinking but is constantly on This is exactly what happens in the video you saw! The camera which records at 30 - 60 frames per second (your eye) adjusts itself so it can only see one phase of bird's wing flap (the blinking light) making it feel like the bird's wings aren't moving (the light is always on)!",
"Let's say that bird flaps its wings about 10 times a second which basically means the bird does the action at flapping wings 10 times which includes it taking the wings up and beating it down let's assume it does this in 3 parts up,mid and down refering to position of wings let's call this sub-frames Now I make a video where I take frames of when the birds wings are down (meaning one of the 3 sub-frames) this results in the video that you saw although it's not that simple to calculate"
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6nxy5w | why did America fail to become the number one producer of solar panels? Wouldn't the government do whatever it takes to gain huge viable markets like this? | Technology | explainlikeimfive | {
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"Because America depends on oil for more than just energy and fuel. Brobdingnagian amounts of money and power are involved with US oil companies, stocks, and even the economy itself in many other ways. Solar means a huge loss for the oil industry (\"Big Oil\") just as hemp threatened the paper industry many years ago, leading to the beginning of marijuana prohibition. A lot of countries are trying to move away from oil dependencies due to both dwindling supply, and the costs involved. But America at this point is far too dependent on it to fully adopt solar.",
"It's not failed, its not being stupid. US business are freaking smart and thought ahead and did seriously good business analysis on this... at least the ones that didn't fail trying to make solar panels. They were stupid. Manufacturing solar panels is a bad business to be in. Demand is low, cost to build them is high, risk is high, and margins are dirt dirt low. This is not a great business to be in. US companies knew this.. but solar is still enticing, but not at the terrible margins manufacturing solar panels will do... so they found a way to make more money: Engineering and science behind solar panels. Thats where the real money is. Thats what those smart US businesses did. Manufacturing them is a crappy business, let someone else do that. Take the real money, the big margins, the business that any Tom, Dick, and Jian Yang can not in any way compete with or create in a rural area of China or India. Engineering and science behind these is killer money, and the US businesses knew that, and got into that business tl;dr: The solar manufacturing business sucks, the US knew and instead got into the better business of engineering and designing them instead of physically building them, you can farm that out to cheap manufactures."
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6ny3u5 | What is the practical difference between png and jpg/jpeg files? | They both store images, but how exactly are they different? It is just a collection of colors and pixels in an order. Is the only difference how the bytes are arranged? If not, what are those differences and how do they affect the common user? | Technology | explainlikeimfive | {
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"There are two significant differences between PNG and JPG for the common user: compression, and transparency. PNG uses a lossless compression algorithm, meaning that no data in the original image is lost or discarded. BMP is another lossless image format, but BMP images aren't compressed. If you save an image in both PNG and BMP format, the PNG will be significantly smaller. The compression used in PNG is best at compressing images with a lot of repeating data, so an image consisting of one solid color saved as both PNG and JPG will result in a small PNG file and a large JPG file. JPG uses a lossy compression algorithm, meaning that some data from the original image is discarded. JPG compression was designed with photographs of real life objects in mind. When you take a picture of a tree, or a ball, or the sea, there are a lot of colors in the resulting image that look identical but aren't quite the same. Think of the thousands of shades of blue that might appear in a picture of the sea, JPG summarizes that by discarding some data that may not be perceivable by the human eye. Because of this lossy compression, a photograph saved in both JPG and PNG will result in a smaller JPG file and a larger PNG file. The downside of using a lossy compression is sometimes important data is lost, this can result in a fuzziness or distortion known as JPG artifacts. If you do a web search for \"JPG artifacts\" you will see some practical examples of this. Images of things like typeface or web art are particularly susceptible to artifacts. The final important distinction between the two is transparency. PNG has support for an \"alpha channel,\" which allows certain regions of the image to be partially or totally transparent. You can think of the alpha channel like the blue screen or green screen used by film producers, an image with transparency can be overlayed on top of another image at a later date. JPG does not support transparency.",
"png is lossless compression. you never lose quality of the original image. jpg is lossy compression. you lose quality. png is good for images with a small color pallete if you're concerned about reducing size and maintaining quality. jpg is better for photographs. if you demand quality and don't care about size, yea sure use png for photographs",
"> It is just a collection of colors and pixels in an order. Nope. Both PNG and JPEG are compressed, but in very different ways. PNG uses lossless compression. It looks for patterns in the image to store it in less space, but when you uncompress a PNG you're guaranteed to get the same image back. As an example, if there are 5 black pixels in a row, instead of storing \"black black black black black\" (encoded as numbers, of course), it could store \"5x black\". The actual compression algorithm used by PNG is much better than just storing repeated colors. It looks for any repeated patterns in the image and reuses them whenever possible. PNG does really well with images with solid colors and simple patterns, like simple icons and computer-drawn art. PNG doesn't do very well with photographs, because there are so few patterns. JPEG uses lossy compression. It stores the image using fewer bytes by throwing away detail that your eye can't see. First JPEG divides the image into 8x8 blocks, and it compresses each block separately. That's why a low-quality JPEG looks blocky. Then it transforms the block into one pixel representing the average color, and then other pixels representing the deviation from the average at different frequencies. This is actually a totally reversible transformation, so it's not lossy yet. The lossy part happens when it stores that transformed block - it uses a lot of bits to store the average color of the block, but only a few bits to store the \"detail\", the high frequency noise. It's cleverly done in such a way that it tries to throw away bits that your eye can't really see, preserving the overall detail well. Finally JPEG images get lossless compression on top of the lossy compression. For photograms, JPEG images are much smaller than PNG, but they lose some quality."
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6o3ji5 | How did game developers for old games like Super Mario put graphics, music, logic, etc using just tens of kilobytes? | A simple image nowadays can be a few megabytes. Oh and how did they use the few kilobytes of RAM they had so efficiently? | Technology | explainlikeimfive | {
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"First on the issue of image sizes: Less pixels means less data right from the start. Say you've got a 256×240 image. Compare to how many pixels you'll have on a 1920x1080 screen! Additionally, there were less colors, less information required for the positioning and values of each pixel. But the tricks; oh the tricks. The NES split an image up into tiles and blocks. 4 8x8 tiles made one 16x16 block, which also means that your image could be done as hexadecimal values. Every memory page contained 256 tiles of 2-bit raw pixel art, but you could repeat it in various locations to save on memory. For example, by having 90% of the sky simply the same blue. Or by having NO background at all (this is also why 'black' was often a bit different from TV to TV). Or at least by repeating certain tiles quite a bit; like in the floor or walls... The NES had 64 palettes. Every palette was a selection of 3 colors plus the shared background. A single palette could be used PER block. So each tile was now just a memory page location and an allowed palette. So the image only needed to call on the 2-bit memory location of each tile, and the 2-bit palette selection of each block. And guess what? The NES? It had 2 nametables, allowing the side-by-side or top-down screen systems in so many games; this is what allowed for the illusion of scrolling, when in fact only what was on screen at the moment 'existed'. Then things get even trickier. Some games would exploit the flickering or the 60hz refresh rate. Recca, for example, is famous for making everything exist only one out of two frames, allowing them to clutter the screen with even more explosions and enemies with two alternating 30fps images 'superimposed' as far as our eyes can tell. Sprites had their own additional memory page, and were used for anything that isn't in the background: Megaman's life-bar was a sprite, while your hearts and bombs remaining were in the background in LoZ. Sprites had their own locations on the screen independent of the background, which was great for the life-bar as you moved, though. An individual sprite had to be 8x8, but the result was that they made most characters into multiple sprites. This limited many games though, because there was a limit of 8 per horizontal line. Anything over that limit would not be rendered, which was going to be problematic when you already had 2 or 3 per line all making the main character. This was the source of much flickering; once player actions were taken into account there was little the developers could do sometimes. There was also the other hardware to take advantage of: The TV! By doing loops or timeouts on certain parts of the graphics, you could take advantage of the tv's vertical blank (these become blatant sometimes once emulated on newer screens) to refresh the picture unit, to change the timing or loop certain cells, which could allow animation or certain effects on the cheap RAM-wise, although those instructions required quite a bit of knowhow and timing to look good. Combined with bank-switching (the art of just reassigning the image to a new position in memory) you could make stuff like waterfalls or 'moving-relatively-to-the-camera' backgrounds. Pretty much every game had its tricks; those are just the very basics and the small handful I know from reading in depth on some of my favorite games.",
"Graphics take up way more room than any code, even MIDIs and similar music formats are basically written in code rather than recorded. For graphics, they had very limited palettes. A sprite that uses 4 colors out of a total of 16 also takes less room than the same sprite using 4 colors out of 256 or more possible colors. Think of it as a checklist you have to fill with Yes's or No's (1s or 0s), would you rather answer 16 questions or 256? No matter how many No's there are, they still have to be accounted for. Blue? Yes, Red? No, Yellow? ... Now imagine that list for every single pixel, thankfully the resolution of most retro sprites was a limited 32x64 or similar. This is why Bitmaps could be saved in 16 colors or 16 bits (In a graphical sense \"Bits\" is half the number of colors that can be shown at a single time and the square of the total number of colors IIRC). Additionally, that 16 color palette is shared among every sprite and tile (platforms, blocks, etc). If each sprite is only allowed to have 4 colors you can group them together with other sprites that use the same colors, monochrome them and paint-by-number. You can see this effect malfunctioning in some romhacks, enemies might be the wrong color because they're in a level that has a different section of the palette assigned. All these space saving measures with graphics and palettes made the difference between kilobytes and megabytes.",
"Adding on to the above they also used a lot of very clever hardware and programming hacks that allowed them to do more with less. It's very interesting some of the techniques they used with color pallets swapping in games that lead to visual bugs we all saw growing up with the system but didn't know why. A great example of a seemingly intended trick is in space invaders where the bugs speed up as you kill more. This wasn't on purpose. The hardware was actually limited so there wasn't enough resources to move all of them at once at one speed. As you killed then more resources became available so they just moved faster. Edit Yes I know space invaders wasn't nintendo. Just using it as an example of clever hacks.",
"Simple answer: Careful coding and reuse of game assets. Those old games were written in super optimized assembly code, and the old consoles had dedicated chips/hardware that made things easier and required less code. Think special chips to handle 2D sprites and music. But, we still do this kind of coding today. Next month in fact. Next month [js13k]( URL_3 ) is on again, a yearly gamejam where game developers get together and make a game using javascript that fits into a 13kb zip file. (There's also js1k. Yup, 1024 bytes is all you get) A theme is announced on the 13th of August and developers have a month to make a game using that theme. Participation is open to all, entry is free, and you get a t-shirt for your effort. For reference, here's some selected entries, these are all 13kb or less. Yes, each game listed here is smaller than the thumbnails on the page. These all play in your browser, no plugins or anything required. (Best to use Chrome) [Evil Glitch]( URL_0 ) [Road Blocks]( URL_2 ) [It's a lovely day for a drive]( URL_5 ) [Super Pinto Rally Racer]( URL_4 ) And my own [Super Dragon Rescue]( URL_1 ) A Super Mario 2 clone with 5 levels and a firebreathing end-boss. These entries are all open source, so you can actually check the code and see what kind of tricks people use to minimize their code and game assets.",
"This video on old school graphics (Super Mario Brothers) answers your question perfectly. URL_0",
"Here's my attempt at a much more 5 year old explanation than what's been given: First of all: When you look at a screen cap of an older video game, it's actually being upsized. Each pixel rendered by the system becomes many pixels when it's viewed on our displays of today. If you viewed the screencap image in actual pixels in terms of the resolution the game was rendered at, it would take up only a small tiny corner of your screen. So there is A lot of your data size difference right there. Secondly: the system didn't render a full still image for every frame. It rendered objects as they came into view and moved them around the screen and swapped them out accordingly. Getting deeper here leads you into the more in depth explanations already laid out in this thread.",
"Not graphics/sound related, but code size and portability were concerns going way back to the text-only adventure games of the 70's and 80's. The authors of Zork wrote a good article on this (\"How to Fit a Large Program into a Small Machine\") URL_0",
"Back in the very old days I used to make games for the Commodore 64. Although it had sprites, they were complicated, could have only 2 or 4 colors, and you could only have 4 or 8 of them. For backgrounds and graphics that didn't need to move that much, you would redefine the character set, basically turn whatever unused characters you had into bits of graphics and then arrange them on your screen as needed. At the end of the program were \"data\" lines, long lines of numbers which the computer translated into the characters. You did the same with music, loading a note, corresponding to a number, into one of three memory locations allocated for sounds. I'm not a programmer anymore, but I think nowadays, a lot of the stuff done like this is accomplished with libraries and things. The program loads in whatever .dll or whatever is needed at the time. Like I said, I haven't programmed since PASCAL. I've always meant to try and learn again but well it's been a long time."
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6o3nh5 | How does AI ever lose at chess? | If a human chess player looks x amount of moves in advance to pick their next move, a computer, not bound by memory constraints, could play every combination of every piece on the board; eliminate all games that end in a loss, select only from winning endings and make a move based on that. Then repeat process after every single move. | Technology | explainlikeimfive | {
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"> a computer, not bound by memory constraints, could play every combination of every piece on the board This, right here, is the flaw in your assumption. The computer is absolutely memory limited, the human actually has an advantage here because heuristics are more efficient but less accurate than brute force. Computers often rely on moves that human chess Masters have made in similar situations in the past There are ~10^43 combinations of a chess board, a computer with a petabyte of RAM only has ~10^15 bytes of memory, still far far short of the complexity of a chess board. A computer will generally only compute maybe a dozen moves out so it can act in a reasonable timeframe",
"There is no existing computer that can look at every possible move all the way to the end of the game. There are more possible chess games than atoms in the universe which means it is impossible to create memory or a hard drive to store them all. However, a computer is able to look ahead more moves than a human, and therefore typically does better than your average chess player.",
"They don't any more, and possibly never will again. There have been some fairly close matches in the last few years, but overall the best AIs are now substantially better than the best humans. Interest in chess has been mostly replaced by interest in Go, which is itself very close to being 'solved' in the sense that the best humans can't win against the best AI, although not solved in the game theoretic sense.",
"It would be possible if a computer wasn't bound by memory constraints. There is something called a [Game Tree]( URL_0 ) which essentially shows every combination of possible states that a game board can be in, and the transition from one state to the next by making a move. For a game like Tic-Tac-Toe, which only has nine squares, which can only be either X, O, or blank, and which has at most 9 possible moves (reducing at each step), its fairly trivial to build out the tree showing every possible state and every transition. If a game tree is produced for a game to guarantee the outcome, that is considered a [Solved Game]( URL_1 ), where if you take all of the optimal steps, you can guarantee the outcome. While its theoretically possible to solve chess, the problem space is too big, and the constraints on modern computing prevent it from being solved today. The most complex game to be solved is Checkers, and even that was with a few caveats restricting the problem space."
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6o43xm | How can large amounts of information be compressed into a short sequence? | For example, some roguelike games with randomly generated runs give you a short "seed" that lets you recreate the exact same run later. | Technology | explainlikeimfive | {
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"Computers can't really calculate random numbers, they can calculate pseudo-random numbers ([more information in past ELI5 threads]( URL_0 ). Most pseudo-random number generators start with a \"seed\" and will *always* come up with the same sequence of \"random\" numbers following that. In a game like that, all the levels are generated by taking random numbers & following some \"rules\" about how to build a dungeon. If you have the same series of numbers, you get the same levels."
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6o4hj6 | What is memory leak and what does it affect when it comes to pc games? | Technology | explainlikeimfive | {
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"To perform tasks computer programs must allocate certain amounts of memory to them. An application is usually composed of many different smaller programming sequences and those programs each will allocate a certain amount of memory to them, do whatever they needed to do, then release the memory to be reassigned. That is usually what happens... ...but sometimes they get it wrong. Sometimes they are written incorrectly such that they do not release all the memory they used. As that sequence is run over and over the memory they used and didn't release builds up and the user sees their free memory \"leaking\" away. Eventually this bloats the program's memory usage to the point where there is no more left and the program crashes.",
"Possibly the worst I can do but: Imagine a 10 truck loading dock for a company. The trucks park, deliver the product, and leave. The fastest and most efficiently the company could possibly operate is if all 10 loading docks are being used at the same time. Here's the memory leak: Imagine one of the trucks doesn't leave and for some reason the driver thinks he's still supposed to be parked in the lot. This makes the company less efficient because it's now unable to get another truck into that lot to deliver more product. Now the company has a 9 capacity loading dock. This will hurt the company as it causes them to operate at a slower rate.",
"For a game-specific example, imagine playing a multiplayer FPS like Battlefield. In order to redraw the playfield ('level') as quickly as you run/are shot around it, its geometry, textures, lighting and effects must all be held in memory (RAM). Suppose one level needs about 128MB RAM; one of the first things that's happening behind the 'loading...' screen is the game requesting 128MB off Windows (or whatever OS you use) in order to store the level data from HDD (or possibly even online). Of course there will be more assets to be stored alongside, like UI graphics and sounds. When you've finished the match, you don't need the level in memory any more, so before the game 'forgets' about the memory location, it's supposed to tell the OS it's done with that 128MB RAM. If you choose to play again, it'll ask the OS for it back again for the next level, fine. But if, due to a bug, the game forgets to tell the OS it's finished with the level memory, by your second match the OS will have issued 128MB *more* RAM on top (the OS trusts the game knows what it's doing, and never actually *knows* what the game's doing). After 32 matches, if you ask Windows how much memory the game's using (with Task Manager, etc.), it'll say, well, over 4GB—even though over 3GB of that might never be referenced by anyone ever again, until you quit the game. That's a memory leak. It becomes a performance problem when the RAM available to the OS starts to run out; the OS will then start swapping the less-frequently-used bits of memory to your HDD to compensate, and this is very grindy stuff (it's also much more complicated than that). This example is very severe, but many programs have small loops running hundreds of thousands of times that request small amounts of memory and in certain circumstances could forget to give it back, and these add up over hours of runtime."
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6o6qfn | Why do popular games of today (mostly kids games I thinking of) seem to be less story-based as they were in the late 90s/early 2000s and more arcade-style as they were in the 80s? | Technology | explainlikeimfive | {
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"Are you talking about mobile games? If so a large part of the reason is because of how developers are trying to make money. Old arcade games were designed to eat quarters so they wanted to encourage you to spend bits of money as you played the game. 90s/2000s console games were designed to make their money on unit sales instead of continued input. Current mobile games are like old arcade games. They lack a large pricetag up front and let you insert money as you play. Thus the idea when making the game is to drive people to want to put more money in over and over, just like old arcade games. Modern day console games (like all the new stuff on the switch) seems to follow more closely with 90s/2000s stuff so I'm assuming that's not what you're asking about.",
"Attention span. and the desire for instant reward/ gratification as opposed to a reward that is built up over a span of the story"
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6o6r29 | How does NVIDIA manages to bring driver updates to such a large and old lineup of GPUs ? | 1. New drivers for GTX 4xx lineup is still supported until today. 2. Every year has at least 10 different GPUs, desktop and laptop. 3. Not to mention with different operating systems either. | Technology | explainlikeimfive | {
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"It's their core business to do this. If they would only support the latest video cards the customers would get very upset and all move to other brands. Also, the nvidia cards all have a fairly similar architecture. Making a change to the new 10xx series or to the older 4xx series is (probably, i don't know exactly what the code looks like) not that different. You can compare this to garages still repairing cars that are older or microsoft still supporting older operating systems."
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6o846j | How does the machine measure oxygenation through the skin of your finger? | I was at the doctors with my kid and the nurse put a clip over his finger wich was hooked to a monitor. How can it measure pulse and oxygenation? PS: I am a first time poster and english is not my native tongue. Be gentle:) | Technology | explainlikeimfive | {
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"The process is called \"Pulse oximetry\". To simplify the way it works, the device which is placed somewhere on the body where the skin is thin, in your case the finger, and it emits specific light wave lengths, and its sensors detects what waves are being absorbed through the blood, giving them a fairly accurate approximation of the oxygenation of your blood.",
"Fun fact: While oximetry didn't come into common use until the 1980's, it's actually a much earlier invention...a physiologist named Millikan had an oximeter working in 1941. It used incandescent lamps instead of a laser, so it didn't have a lot of resolution, but it delivered useful data on pilot respiratory problems during WW2. The Millikan instrument and its supporting electronics took up a whole wall of a lab, and you can see it in action in the 1942 film *Dive Bomber*, with Errol Flynn as a Navy flight surgeon.",
"Hi! Pulse oximetry does indeed measure blood oxygen concentration by measuring absorption of specific wavelengths of light. However, it is important to note that these devices actually measure the bound hemoglobin (Hb) inside red blood cells. This is typically fine, however CO (carbon monoxide) binds to Hb thousands of times more strongly than O2 (oxygen). For this reason people rescued from fires, and fire fighters working a blaze need their O2 testing preformed with special pulse oximeters that use an additional light source to detect CO bound Hb and subtract it from the percent of O2 bound Hb, in order to obtain the correct percentage of Oxygen in the blood. Also of note is that since this is a percentage, it only determines relative O2 bound Hb, not absolute values. If you were anemic (or hypovolemic) with 100% O2 binding, you still might not be meeting your bodies oxygen demands.",
"Samsung phones can do this, too. I can test my pulse and my blood oxygen level with the Samsung Health app.",
"The real questions is - why can't I and other athletes get an earring that does this, so that I can track real time while doing intensive cardio or weightlifting without having a fiddly thing on the finger?? The tech is there and relatively easy and the (never used) patent expired in 2012. They already do it on earlobes sometimes, so earlobe is the perfect place for it. C'mon chinese manufacturers / kickstarter entrepreneurs!"
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6o8eck | Why do some online merchants need your card type (Visa, Mastercard, etc.) when entering info and others do not? | When buying things online I've noticed that some online merchants require more information when paying with a credit card than others do. Why are some merchants able to figure out card type and others aren't? A related question is why (in the United States, at least) do some gas stations require a zip code when using a credit card and others do not? | Technology | explainlikeimfive | {
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"Because some are more sophisticated than others. The first digit tells you the \"team\" of the card: 3=AMEX, 4=VISA, 5=Mastercard. If your lazy programmers don't code this up, the user has to enter it. Gas stations are a great place to check to see if a card is cancelled, because they are automated and every evildoer needs gas. As a result, they have a lot of fraudulent transactions. To discourage this, they are checking the ZIP online with the CC company. Mostly this hurts foreign visitors, because it makes their cards not work.",
"You can figure out the card type from just the numbers, so you don't _need_ to ever ask for it. The reason they do is to avoid getting stupid emails. You see, if they only accept let's say Visa and MasterCard, and they state this on their website, _people don't read_. They'll just ignore that, try the transaction anyway, and then get declined. _Then_, they'll fire off some stupid angry email rant to customer support where they whine about \"why was my Walmart store card declined?\", which some poor schmuck has to deal with. However, if you give them a drop down box and make them _select_ their card, then when they can't find their Walmart store card listed there, maybe a cog will slowly start turning in their brains and they'll figure it out. You don't even need to use the value they select, it's some basic psychology to make idiots stop and think.",
"Often it's simply to communicate to the customer what cards are accepted. If my company takes Amex, Visa and MasterCard, but not Diner's club. I could put some pictures or a list of the cards I take. But a lot of customers won't read it. They then complain that my site is broken. If I make them pick the type, they *have* to look at the list."
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6o8p1z | Why is there such a difference in USB cables when technically it's all supposed to be "universal" anyway? | For instance, if I get a cheap USB charger/cable from china it may make my phone go trippy whereas a proper one won't. Also, there seems to be brand specific USB cables too that certain devices "work best" with. Why come? | Technology | explainlikeimfive | {
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"The brand specificity is a myth spread in order to make sure the user is using a proper cable - the original cable is guaranteed to be good quality while any other cable isn't. There are multiple reasons to why a bad quality (\"Chinese\") cable will not be good for your phone: 1. Quality: the wires aren't thick enough, or the insulation is bad, or the cable is simply more prone to breaking. These cables might work the first time but might cause problems later. 2. Non-standard cables: USB is a specific, defined, universal standard. Cheap manufacturers simply won't implement these standards correctly, because it is cheaper not to do so, allowing them to sell cables cheaper and/or make more money. 3. Different standards: a lot of phones these days come with some sort of a quick charging technology. A cable that barely meets the standard - or doesn't at all - is more prone to breaking under the pressure of this increased current/voltage that the USB spec doesn't account for, but quick charging requires. 4. Quality assurance: a cable from a reputable brand is more likely to work and keep working because they're more likely to have proper quality control measures in their factories.",
"USB is universal in the sense that you can take the four wires and conenct them to two machines, and they will be able to talk to each other without further intervention. The different connectors all just use the same set of 4 cables, so all you have to do is pick the most appropriate connector for your use case, and hook it up to the correct pins on a standard USB controller chip in your electronics. This is in contrast to the legacy RS-232 serial port, which is most popularly found as a 9 pin connector, but could also be found with other form factors with varying numbers of pins. On top of the differences in numbers of pins, the old standard of serial connector had a sort of standard default configuration, but there were a lot of options you could set, such as bit-rate, that would prevent communication if it was not set correctly.",
"Cheap chargers can be a \"kill your device\" hazard, or even a \"kill you\" one. Sometimes the circuit design and construction puts very little isolation between the mains side and the USB output, meaning you are at very high risk of a fault developing which could be lethal. (best illustration, Big Clive's [\"Pink USB Charger From China\"]( URL_0 ) video) Also, there is (for generic USB devices) an evolved standard of power supplies \"advertising\" the current that can be drawn from them by having certain values of resistors across the USB data pins - this allows a phone to know if it's safe to take more than the base standard 500mA (0.5 amps). If a charger advertises \"I'm good for 2 amps\" but it's really not built well enough to supply that safely, it could get hot / go up in smoke / start a fire. Some devices use a proprietary quick-charge system, where a special charger is recognised by the device and they agree to deviate from normal USB power behaviour to charge the phone quicker. Also, USB-C chargers might either be \"fairly dumb\" (where they behave like a traditional USB charger), or they might implement USB-C Power Delivery - where the charger is a smart thing which negotiates with the device to allow much faster charging by switching up to a higher supply voltage. A laptop with a USB-C power supply connection (new macbooks, some sexy modern Windows machines) just won't charge at all if you plug them in to a \"USB-C but it's dumb\" supply. Just to make things more fun - USB A-to-C cables (USB-A is the regular \"on your PC for plugging stuff in\" type) are supposed to have some specific wiring (a resistor across a couple of the USB-C pins) to warn the device it's going to a \"legacy\" port and it needs to be careful about the power it tries to draw. And many MANY cheap crummy cables of that type either don't have that, or have the wrong one, potentially causing a USB-C phone to draw more power from the other end than is appropriate. And some devices can't cope with cheap crap power supplies, if there is a lot of electrical \"noise\" on the provided power. Cheap cables can use very thin-gauge wire, meaning they might heat up a bit if a device is drawing 2 amps. The connectors might be cheap or poorly soldered to the wires, causing either heating or unreliable behaviour. Buying decent USB accessories the first time is cheaper than buying a new phone if it gets fried. (Personally I've standardised on Anker for USB chargers and battery packs because they seem reliable for me and they're big-enough to have \"something to lose\" if they put out crap that starts a fire)"
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6o999n | What is LPCM on my stereo receiver? | I moved into a new place, and my audio is suddenly delayed and when I looked into it, I noticed LPCM on my receiver screen that wasn't there before. I don't know what that is, and I tried googling it, but it went right over my head. Could this be my problem? | Technology | explainlikeimfive | {
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"Linearized pulse code modulation. It's an alternative coding to DTS or Dolby surround sound. You probably need to cycle through settings to get to whatever input code you normally use. DTS or Dolby are way more common."
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6oahcu | Why isn't HTML considered programming? | Technology | explainlikeimfive | {
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"Because HTML doesn't do the things that that programming languages do. It can't make decisions and it can't loop. You can't give it a list of numbers and have it sort them or find the average, something all programming languages can do. HTML is about displaying text and images and creating hyperlinks. That's why it is a markup language and not a programming language. That said, it is possible to embed a programming language like javascript into HTML, and once you do that, you start to incorporate programming tasks into your web pages.",
"For the same reason that word processing isn't considered programming. All you are doing is writing text, and controlling how it appears.",
"Because HTML doesn't allow you to change behavior. It only allows you to mark the content with a tag, depending on the browser to whatever preprogrammed behavior for that specific tag or set of tags. Programming is cooking with ingredients. Markup is ordering food food menu item #5"
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6obmuh | When filling out an address form online, why do websites ask for City and State, before Zip Code, when the Zip Code could be used to autofill the other information? | Technology | explainlikeimfive | {
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"1. Design decision, people are more used to address being address/street, city, state, zip to the point that it's an automatic reflex to enter things that way 2. It's extra work to maintain a database of zip codes and cities or tie into an API that provides this service",
"It provides a validation data point to make sure it's correct. Why even bother with a zip codes if you have a number street and city? Surely USPS mapped it all already. Yea... And they use address+city to check against the zip code when it runs thru the automatic mail sorter. If they don't match, it gets kicked out and someone looks at it and tries to guess which zip code processing center it should go to",
"> when the Zip Code could be used to autofill the other information? Actually it can't. A zipcode can cover multiple cities, so that is important information to have."
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6ocuq8 | What is 5G and what would it mean if a cable company was investing in it? | Technology | explainlikeimfive | {
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"5G is a blanket term for what is being dubbed the next generation of wireless uses, to include things like faster mobile data, internet of things, and plenty of other uses that we haven't yet nailed down. IF you ask a dozen people, in the industry what 5G will do, you'll get a variety of generic answers, plus each one will probably tell you \"we don't know yet, but we know it will be important in the future...\" All telecom companies are investing in wireless applications such as 5G as an area that the world is moving to. Nothing interesting there. Just another step towards the future of connectivity, and everyone is getting in on the action."
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6ode2m | How do IT departments handle frequent cyber attacks? | Context: the director of my organization's IT department mentioned in a presentation that we encounter hundreds of cyber attacks every week (this organization is well-known globally). How is it possible that we are attacked so frequently and how do the IT folks handle it? I know nothing about CS. | Technology | explainlikeimfive | {
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"Almost any publically accessible IP address is constantly bombarded by various attacks and scans. At home your router most likely protects you from a direct assault on your home computers by forbidding direct connections unless you've explicitly set up your router to allow it. Same is true in the corporate world. Depending on your organization's IT department, budget and policies they may have one more of the following * Firewalling routers that block desirable internet traffic. * Application level proxies, that check internet traffic, inspect it for undesirable content and relay it on to the actual application. * regular updating of software and applications and virus scanning * various intrusion detection systems that monitor what applications are running on various servers, a fingerprint of various files on the servers and what type of network traffic patterns those servers typically have. * Maybe even a honey pot system which can mimic vulnerable targets that appear to be easy targets. Once an attack on a honeypot is detected, steps can be implemented to block them."
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6of2cy | My computer just told me that it was unable to perform a simple task. I tried the same thing again immediately after and it worked. This seems to happen regularly with computers. How can this happen? | Im pretty sure this happens with a lot of devices like games consoles and smartphone. 1 second it cant do something and then it can do it straight after. | Technology | explainlikeimfive | {
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"This question is far too vague to be able to answer with any accuracy or certainty. But in a very general sense, it is exactly what it sounds like. Sometimes the computer may be in the middle of something that was using a particular resource or it was unable to process what you were asking at the time or a wide variety of other reasons. But this is one of those situations where each case is very different and can be caused by a wide array of different things."
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6oggeu | What prevents a television show that no longer airs to sell its rights to Netflix or some other streaming service? | I was just thinking about shows I watched as a kid. Clone High, Buffy the Vampire Slayer, Undergrads, etc. and was wondering what the incentive was to not have them highly accessible. | Technology | explainlikeimfive | {
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"It may be stuck in licensing purgatory, or someone else still owns the exclusive rights. In some cases it's no longer really clear exactly who owns what percentage of the content. TV shows use licensed music, have multiple actors on different contracts, and have various production houses, publishers, and distributors that may all need to agree on a deal depending on how their original contracts were worded. This can get cumbersome fast and shows that have multiple organizations with veto power over a new deal can get tied up in licensing talks for years. It's also possible that a single entity has already taken the steps to consolidate all that into a single deal and is working on their own service or simply is asking too much fron Netflix.",
"Quite often it's the music. When the show was created they license the music for TV distribution only, maybe DVD as well. Now when they go back to get a streaming license for the music, the author / performer wants a ton of money, making it not worthwhile. So they can either spend the time and effort replacing the music, which often happens or just say it's not worth the effort at all.",
"Just because a TV show is not currently on air, doesn't necesarily mean that nobody has the right to air it. A network could've locked in the rights to air that show for the next five years, for example, and even if they never put it on air, those rights will still belong to them. Similarly from Netflix's side there is always the question 'is this worth it'. Even if the show is relatively cheap (it is not like they get them for free), they still have to ask themselves 'can I spend this money better'. Instead of buying three cheap shows, can they instead buy one more expensive one that they feel people will watch more? Or can they instead sink that money in another original project of theirs.",
"There are a lot of reasons a show or movie might not be on a particular streaming service: * The company that owns the rights is planning their own service. * A different streaming service has bought exclusive rights. * The show or movie is still selling DVDs and the owner doesn't want to risk slowing down DVD sales by offering streaming. * There are complex licensing issues that make selling streaming rights difficult. * Whoever owns the rights just doesn't care enough. Take Buffy, for example. Episodes are available for sale on Youtube, Amazon, iTunes, and Google Play. It's an old show, but also a popular one, so chances are episodes are still selling and whoever owns the rights thinks they'll get more from those sales than by selling rights to Netflix."
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6ohhk5 | Games (espacially back in the day) try to use as minimal space as possible for their games, so why are unused graphics etc. still in many gamefiles. | It kind of seems paradoxical. | Technology | explainlikeimfive | {
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"you never know what removing something can do. say they removed unused graphics from sonic 1 for a stage they didn't intend on using anymore. for all they know, removing that code could cause a huge glitch or crash elsewhere and it would be even more of a headache to fix that at that point. so sometimes it's safer and easier to just leave the unused stuff in, untouched.",
"Old graphics generally used things called Sprites. These were very large sheets of graphics that could be divided into X by X square cells. The graphics processor on the old console would load an entire sheet into memory and then could reference a specific gridpoint on that sheet to pull up an image. This means you would find certain sprites with each other regularly. For instance, you might put all the stage-specific enemies for one stage of Megaman on the same sheet. What this ends up meaning is that, if for some reason you don't fill up the entire sheet, you'll have some lost 'theoretical' space -- the space on the disk is still consumed, just with no value added from it. If you had a sprite that you were using for something that was eventually taken out, you might not necessarily want to take the work to remove it from the sprite sheet. You don't gain anything by doing that work, and can potentially cause other problems."
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6ohzew | How come the file size of my camera's photo are always different even though the same amount of pixels are being recorded? | When I take lots of photos with the same picture size (8megapixels for example) some photos are 6MB file size and others are 2MB. I know that the pictures are different, but in every pixel the information is recorded the same way, and I get very different file sizes. Why does that happen, if the amount of pixels being recorded are the same? | Technology | explainlikeimfive | {
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"not an expert but this is what i would think. your camera captures and stores images using file compression. it is not storing raw data straight from the image sensor. if there are many pixels that contain similar data (same color/exposure/etc), the group of pixels can be compressed by storing the color/exposure data as a single pixel, then the remaining pixels which are identical are stored as references to the first pixel, the \"reference data\" in the following pixels is of lower size than the original color data. files with a wider range of color and exposure should have less compression than those with many similar pixels. this is one method of file compression, there are many. someone confirm this please",
"'Twas oft asked here. Ye may enjoy these: 1. [ELI5: Why do two images with the same dimensions and file type have different file sizes? ]( URL_1 ) 1. [ELi5: Why aren't all the pictures I take with my camera the same file size? Isn't it always the same pixel density, and each one has to be represented? ]( URL_2 ) 1. [ELI5: Why do digital photos have different file size with the same resolution? ]( URL_4 ) 1. [ELI5: why does the file size of digital photos vary when the pixel count doesn't change? ]( URL_0 ) 1. [ELI5: Why are some pictures file size larger than others? Even when the same resolution? ]( URL_3 )"
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6okg8m | Why do doctors' offices often use those weird scales where you slide those two metal brackets over numbers until the tip balances? Are they more precise than the digital scale I bought off Amazon for $20? | Technology | explainlikeimfive | {
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"Mostly cost honestly, commercial electronic scales are expensive. [A quick google puts them at $375]( URL_1 ) where the old style are only [$175]( URL_0 ) And really, why would they ever buy a new one? How long as that doctors office existed? They probably bought the scale 20 years ago and haven't had to replace it yet. Also, the electronic ones are spring based, and can suffer somewhat from drift errors when their springs age. They need periodic calibration. The balance style is much less sensitive to this, their wear modes don't really screw with their calibration (that would only happen if you chipped the weights).",
"Why does your office phone still have a cord? Because it works every, single, time you pick it up. It is cheaper, and your office already has it and has for the past twenty years so why put money into changing something that isn't broken. As the boss if someone pitched you cordless phones all you are going to think about is the handsets going missing, batteries dying in the middle of a call, problems problems propblems over a system that works flawlessly now. Why buy yourself a headache.",
"You probably step on your bathroom scale < 10 times per week. The doctor's office scale is stepped on > 10 times per hour. They can't just say \"Darn, the scale broke, we can have another one in two days\". That puts durability in a different cost light.",
"It is the difference between a \"scale\" and a \"balance\". Scales measure weight(downward force due to gravity on an object) by the use of springs or electronic load cells. Balances measure mass, an intrinsic property that is independent of the force of gravity by comparing the downward force on the object with the force on know masses (those slides on the doctors scale. Not for nothing, but your doctor's scale (balance, really) would yield the same result on the surface of the moon. Your digital scale would not.",
"Those are old scales but they work well. Digital scales are expensive. They are not more accurate. I work in the medical office, we have 2 digital scales but the boss only replaces things that break. It's funny because the digital scales frequently are touchy but those old ones probably will work forever.",
"Electronic scales uses cells to measure the **force** you excerpt towards the ground. It is technically a dynamometer, and it's not really accurate. Those scales you see at clinical facilities are comparing two weights using a lever mechanism. It is really accurate, doesn't need batteries and keeps calibrated for a long time.",
"I grew up in St. Johnsbury, VT. Home of Fairbanks Scales, who owned the original patent on the counterbalance scale. The invention funded much of the town’s development tough the family’s generosity. (Schools, churches, museums, etc) What most everyone is saying here is true. Counterbalance scales are more accurate, gravity varies around the earth and solar system, but mass does not. In theory a digital counterbalance scale could be made, but it would be far more expensive than the current models, which last decades and are easy to use. Next time you are in northern Vermont, visit the Fairbanks factory or museum. More details URL_0",
"They're easier to give maintenance, not to mention that they are also used to measure height, digital scales that measure both are even more expensive. There's really no difference in their accuracy, and the mechanical scale has a lot of durability, so they're just overall a better choice.",
"Wow my turn to shine! Price Durability Calibration The scale that you describe is known as a sliding balance. Expensive but accurate and will last forever. Calibration doesn't need to occur unless something catastrophic happens as there's little wear and tear on the actual weights. Electronic scales use a device called a pizeoelectric force gague. It's the most expensive component and also the bit that manufacturers skimp on. Cheap scales can't be calibrated, and also are not very accurate. So why the fuss? Because clinical guidelines and protocols work on ranges. For instance, bmi 29.9, you're overweight. Bmi 30.0. you're obese and need a whole different regime. So.accuracy is important. As is the capability to calibrate to ensure consistency. Source: honours medical school OSCE for distinction.",
"They will last a lifetime. Electronic scales are now cheaper but I bought a couple at 40 - 100 bucks each and they only lasted a few years.",
"I think those old ones are more durable and less prone to malfunction. A digital scale can be susceptible to several issues in the time you own it and realistically need calibrating every few weeks if not days with heavy use. Even the analog scales can suffer issues from gears breaking to the needle bending and need to be calibrating. A hard stomp can cause those kinds of scales to be off by a few lbs. the scales with the slides and weights don't need any real maintenance and are usually highly accurate over long periods of times. Plus they can handle much larger weights as well while still being relatively cheap."
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6oliit | Why do some headphones have a frequency response of 40KHz even though human hearing range is only 20KHz at best? | Technology | explainlikeimfive | {
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"I can only think of two reasons; 1. A bunch of 'headroom' above and below what we can hear means no compression is needed. 2. I suspect its simply a marketing ploy.",
"Like someone else said: it's hard to make a small speaker have that tight of a roll off without distortion. Also, some harmonic freqs outside of your hearing range can still be felt even if not actually heard."
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6olnoi | How can cable TV service work well nearly 100% of the time while internet service from the same provider can be so wildly inconsistent? | Technology | explainlikeimfive | {
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"TL;DR: The machines that handle internet traffic are more complicated than the ones that handle cable. Internet traffic accesses more locations and sends information in two directions. Cable is handled by centralized locations and only sends information one direction. ----- When you subscribe to cable, you are paying to access One Company. They may have a few buildings or servers across a country, but not a huge number. Because this company is large, they make sure that access to their services are stable. When you communicate with these locations, the information is almost entirely one direction. The Cable Company sends information to your house, and your house receives the information and displays it. End of story. The signal going to your house is exactly the same as the signal going to every house that subscribes to that provider. This means that the equipment that handles signals is rather simple - one direction, and all information is the same regardless of location, and it all comes from a small number of locations. When you access the internet, things get a lot more complicated. You access a huge number of different locations, each location being a different size than others. Some websites are hosted in warehouses by large companies, others are hosted on a Windows XP computer in someone's basement. When you access websites, you receive information and your computer send out responses - information goes both directions. When you access a website, the information going into your house might be different than information going to your neighbor. This means that the machines handling the information must be a lot more complicated. Because the machines handling internet traffic are much more complicated than those handling cable there are more components that might jam or fail. There are a couple of other things that come up depending on what you mean by \"wildly inconsistent.\" Sometimes a website might be down even though you can access other websites. This is caused by an internet outage where the server is located. If the website belongs to a large company (like reddit) they usually have redundancy servers, so that if one goes out another handles the traffic until the original goes back online. Small websites can't do this because it is expensive. Cable companies don't suffer from this because they are always large companies with redundancy built in to their systems, in addition to being less likely to suffer from an outage.",
"Your'e getting all your TV content directly from the provider. Internet content can be coming from all over the world. The connection to your ISP might be working 100% correctly, but someone might've dug up some fibre by accident in Middle Of Nowhere, Alabama and taken down dozens of websites.",
"Tv is a broadcast meaning that the tv service provider is just sending information. There is no (or very little) conversation back from any customers equipment to the tv service equipment. They are always sending the tv information out. In the internet, you have to have a conversation for anything. You have to request a stream of information to start, called a SYN or synchronize. The other end sends back their own SYN and an ACK or acknowledge. Finally you send back your own ACK, and that's just to start the conversation. There are other ways to do this, but suffice to say that is how the majority of communication on the internet starts. All along the way, each piece of equipment has to do little bits of work to make sure your information goes to the right place because if it doesn't then it gets thrown away and your computer waits... then asks again. If it takes too long and never gets a response after asking a few times it \"times out\". There is much more to it, but TV only equipment is dumb and just sends channel 12 to everyone (that is subscribed) all the time. Network equipment has to think and be smart and deal with a two way conversation. There are several points of failure and service levels really fluctuate. In the end, tv is simpler to not mess up. Edit: a little bit more about service levels. Let's say you're at home at lunch and only a few people in your neighborhood are also home using the internet. You will get close to the speeds you expect, given what you pay for and what you're used to at that time of day. If you pay for 200mbps and see speeds actually at 150mbps, that's pretty good. Now it's 7 in the evening and everyone is home in the neighborhood watching Netflix, or YouTube, or streaming pandora, and everyone has multiple devices doing this all at once, now you are experiencing speeds around 20mbps or worse. All of this is changing real time. What is happening here? Well you're not sharing your 200mbps with the rest of the neighborhood. And they may pay for higher or lower speeds too. What's actually happening is a network node near you is being overloaded like the roads are during rush hour. It wouldn't necessarily make sense for all the roads to be 8 lane highways all over town just so rush hour doesn't slow down. Likewise it doesn't always make sense to ISPs to have equipment always capable of handling every single customer at full speed all the time. What if some people stop getting internet, or decide to go to a lower tier speed? Then you spent more to support something that isn't being used. I'm personally in favor of everyone getting better speeds and more reliable internet, but it's someone's job to manage a company's money."
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6op0u2 | If satellite phones provide near universal coverage and have been around for such a long time, why didn't they become the norm? | It worked for pagers, right? | Technology | explainlikeimfive | {
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"There are multiple reasons but one of the biggest is the cost to make and receive calls. From Wikipedia: > > > The cost of making voice calls from a satellite phone varies from around $0.15 to $2 per minute, while calling them from landlines and regular mobile phones is more expensive. Costs for data transmissions (particularly broadband data) can be much higher. Rates from landlines and mobile phones range from $3 to $14 per minute with Iridium, Thuraya[22] and Inmarsat being some of the most expensive networks to call. The receiver of the call pays nothing, unless they are being called via a special reverse-charge service. > > > Making calls between different satellite phone networks is often similarly expensive, with calling rates of up to $15 per minute. > > > Calls from satellite phones to landlines are usually around $0.80 to $1.50 per minute unless special offers are used. Such promotions are usually bound to a particular geographic area where traffic is low. > > > Most satellite phone networks have pre-paid plans, with vouchers ranging from $100 to $5,000. Most people are not going to pay that much for themselves much less buy satellite phones for their kids.",
"The cost associated with transmitting data too and from space is insanely high. Commercially, data is multiplexed together and sent in a giant stream from land to space, and then back again at the distant end. It's like a giant super-highway of data. That's cool, efficient, and fast. An individual stream of data going from the satellite to JUST YOUR PHONE is like building a super-highway to every single home in the countryside - it's still possible, but the return on the investment just isn't worth it. The resident of that home (user of the sat phone) has to pay for that highway and now can't afford to drive to work. Satellite communications providers like Direct TV have one major up-link to the bird, and then a single down-link. When you pint your receiving dish, you're just listening in to whatever's already being broadcast, you're not changing the requirement of the signal in any way. A sat phone requires a direct connection from the satellite to you, and you're the only one who can use that receiver at that frequency on that satellite at that time. Limited bandwidth + expensive cost of building/launching the satellite = high cost of calls.",
"There is a significant time delay in satellite phones and that makes them less desirable than cell phones The satellites are generally in geostationary orbit 32000 km above earth which means it takes about 1/8 seconds for the signal from Earth to get to it. If you're on a satellite phone and calling someone else on a satellite phone on the same satellite there is a 0.25 second lag in each direction. When you stop speaking they'll hear you stop speaking 0.25 seconds later, begin their reply, and you'll hear it 0.25 seconds later, leading to an extra half second before you hear them reply. If it has to go phone-satellite-base station-satellite-phone then there is a full second of lag, the signal will have travelled 256,000 kilometers! This is undesirable for standard users Your standard cell signal travels a few kilometers to a tower then on fiber then to a tower then to the phone. The circumference of the Earth is 40,000 km, even with crappy routing you won't force the signal to travel more than 80,000 round trip for a worst case lag of just 0.3 seconds if you call someone as far away as possible. Still only 60% of the lag of calling your neighbor on a satphone",
"Unreliable in adverse weather. I had satellite once. Everytime it got cloudy, connection would go to shit.",
"First, pagers aren't satellite based as far as I know. They use local radio signals just like cell phones. People think satellites are used for everything but fact is most of your telecom comes from tons of wires and radio antennas spread across the globe. Look up undersea cables if you want a good time. Second, in addition to line of sight issues, satellites are really far away. It takes longer for radio waves to go up to space, back down, and to your destination than it does to just go across the planet's surface to your destination. Even at the speed of light, you're talking about a perceptible delay that can be annoying when you're trying to have a conversation."
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6opkz8 | How do passwords in older video games work? | I'm talking about the passwords used to pick up where you left off in games, before saving was widely used. How did a password "save" all progress, including in some cases stats, game elapsed time, etc? | Technology | explainlikeimfive | {
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"Everything in a game is pieces of code, and a password simply ties a bunch of those pieces together to recreate a certain set of circumstances and accomplishments, whether it's “JUSTIN BAILEY” in *Metroid* or opening Dr. Wily's castle in a *Mega Man* game. EDIT: Corollary: Game Genie/Shark codes would often set certain values to maximum allowed and/or lock them there eg infinite lives/HP/Mana.",
"The \"password\"'s generally just a code with, in addition to junk data, the data that's actually being 'saved' (not saved, just showing you the correct code for your current status). Especially when you're dealing with hexidecimal (base 16 instead of base 10), it doesn't take a ton of space to save these details. You have 2500 points, elapsed time is 12 hours 2 minutes 2 seconds, you're on level 6 and have 14/30 hitpoints? Well, points are probably in increments of 10, so that could be essentially stored as 250 - in hex, that would be FA. Elapsed time is probably stored in seconds, so that'd be 46222 or B48E in hex. Level could be represented by just that single character, and current HP as E, max as 1E. So all that data only takes up 10 characters. If it's a 20 character code, there's a bunch of junk data in there to discourage people just giving themselves extra stuff, or room for stuff like inventory, etc",
"You already have some good explanations but to solidify it here's the codes for Megaman 3 and how you can actually build your own code : URL_1 It was a [grid code]( URL_0 ) A dot in a particular position represented a certain thing in the \"save\" for example dropping a dot in C4 and D3 would give you a \"save\" where Needleman and HardMan were defeated."
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6opocc | How do new crypto-currencies keep popping up? Can anyone create a new currency if they have people willing to invest in it? | I just don't understand how these new currencies keep popping up and what gives them value. I suppose with our current system(U.S.), the only reason it works is because people believe the dollar holds value, but you can no longer trade it in for gold for example. I assume the same true for these crypto-currencies, but what requirements are needed in order for these new coin-based systems to start. It all seems like people buying and selling schrute bucks and paddys dollars from an outside perspective. I guess I am confused on how these crypto-currencies are created and where the accountability falls. | Technology | explainlikeimfive | {
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"> I suppose with our current system(U.S.), the only reason it works is because people believe the dollar holds value That's pretty much how all value works. Also known as the Tinkerbell Effect: something being true if many people believe it's true. > but you can no longer trade it in for gold for example What are you talking about? Of course you can trade dollars for gold. You can trade any currency for gold. It's just like buying/selling any other commodity. You've pretty much nailed it with \"people believe it works, therefore it works.\" Any schmuck who comes up with a new cryptocurrency might gather some following and garner investors. Of course, legally speaking, it's a clusterfuck, as there have been arrests and legal trouble regarding cryptocurrency. People do use it for illegal endeavors, like hiring assassins, extortion through ransomware (remember WannaCry?), or money laundering. It's pretty easy to perceive it as a mess, though I find \"real\" money to be just as messy when you think about it for too long.",
"Essentially yes, all you need to make any currency is a group of people willing to trade the currency for commodities amongst themselves. If you wanted to, you and your group of friends could agree to exchange \"slap debts\" to each other in exchange for favors, and that would be considered a micro-currency. Generally, the important thing about a currency is a guarantee of some level of scarcity. The reason we trust in the dollar is because we believe the US Government isn't going to start printing dollar bills like the Weimar Republic. The reason people trust in cryptocurrencies, for better or worse, is typically because the process of mining them becomes so computationally expensive as to be unworthwhile. Therefore, despite there being no overriding government body to trust in, the laws of physics and things like Moore's Law help ensure that the scarcity of the currency is maintained. Cryptocurrencies are very much like a Ponzi scheme. You can make a lot of money from getting in at the right time, but for every person that makes $1,000,000 there's 1000 people that lost $1000 because they bought in at the wrong time. But if nobody else buys in, then the currency never takes off and you've wasted your investment."
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6opqs2 | What tech has allowed devices to be able to run for higher amounts of time on batteries or even allow devices which would have required AC power on batteries? | Technology | explainlikeimfive | {
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"text": [
"A combination of better batteries and electronics which use less power. LCD uses less power than plasma. A 1.2v CPU uses less power than a 5v one. Doing more with less power and better batteries equals long life."
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6oshg7 | Why does food reheated on a gas stove taste different from food reheated with a microwave? | Technology | explainlikeimfive | {
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"This gets asked a lot in a lot of different ways. Basically it's the same reason any food tastes different when cooked in a microwave vs being cooked over actual heat. Microwaves don't heat food, they heat water (mostly) and that water heats the food. As it vaporizes, it can take with it the compounds that are responsible for taste and smell. A heat source like a gas burner on the other hand applies heat to the food primarily (also the water inside it I suppose, but rather than exclusively applying it to the water, it applies it to whatever it's touching) which allows Maillard reactions to occur on the food's surface. (Basically carmelization that gives food a nice crust full of flavor.) Boiled and steamed foods will taste pretty much the same when cooked in a microwave or on a more traditional heat source because they also rely primarily on heated water to cook the food."
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6otoai | Why does the teletext/videotext in television looks that old and hasn't been updated (at least the appearance) since ages? | Technology | explainlikeimfive | {
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"text": [
"The system has not been updated because it's being replaced by the Web. In fact many companies are retiring their use of it completely."
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6ov4bb | What does clearing cache and cookies do? | Technology | explainlikeimfive | {
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"Cookies are little files stored by websites. They contain information that the site has to temporarily leave in your computer, like the fact that you are logged in or that you have closed the cookie prompt or your personal preferences sometimes, if you are not logged in on YouTube for example, it uses cookies to remember what videos you watched and give you suggestions based on it. Cache is temporary memory used to load sites that you have already visited or that you visit often faster. When either of those get corrupted, it may make some sites load not like they are supposed to. In such cases, cleaning your cookies and cache might fix it. *I’m not an expert though, correct me if I said something wrong.* Look it up on Wikipedia if you want to learn more about them: [HTTP cookie]( URL_1 ), [web cache]( URL_0 )"
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6ova1e | How does internet speed works? Why is so different between companies, locations(different countries as well) and time? | Technology | explainlikeimfive | {
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"I'm European so I don't know the US situation, btw: There are basically 2 types of internet connection, with copper or optic fiber cables Copper cables are old and can't carry more than 20mbps, and nobody can get more than 15-16 because copper is pretty sensitive to electromagnetic interferences, so in the recent 3-4 years internet providers are starting to invest money on optic fiber connections Optic fiber is basically a glass wire who carries light impulses, it can get theorically any speed but today's technology can go up to 10Gbps (10.000Mbps) in particular conditions Most of the European and i think US citizens have access to 100Mbps or 1Gbps optic fiber connections Usually one company gets the money from the state to install optic fiber cables, this company after 2 or 3 months gives access to his cables to other compains who resell it for 5-10 euros more and usually add something like unlimited phone calls or a better wi-fi modem"
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6ovmce | Where is the live sporting event footage stored after they are aired? Do networks have all the footage, even the angles that weren't shown in a huge archive somewhere? | Technology | explainlikeimfive | {
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"Depends on the networks. Sort answer is, yes. Some of it might be discarded later, but that is a matter of decision for the network or for the league. Basically, for all the footage the network didn't air, is it worth it for them to save it somewhere, or is it not worth the cost of saving the storage space. Storage is so cheap now, that usually it gets kept. One thing the NFL markets now is a thing called \"all-22\" film. Its pretty cool if you LOVE football. When the NFL films a game, there is a camera up high that has a view of the entire field (and thus every player on the field, \"All 22\" of them.) It doesn't make for good game coverage, so that's why you don't see the angle on TV, but for the coaches to review footage and figure out what happened, they need to see everyone. Who went were and what as the play developed. Since so many fans are getting really into watching and understanding the finer points of football, breaking it down in their own blogs and reviews, NFL now allows fans to subscribe to the coaches film view too."
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6ovurw | If i own a device like android phone, why is it so hard to get full privileges? | If i own it, i should have full access to its functions and not just part of them. Why would manufacturers not make it easier for advanced users to take control? | Technology | explainlikeimfive | {
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"i assume you are asking about root access, well most phones have a 1 year warranty period so during that period even though you paid for and own the device you are the secondary user and the manufacturer is the primary . now if you are an amateur who doesn't know much about the phone and they give you root access you might go to the root files and mess up some stuff and they will have to fix it .and giving root access will also mean giving you the ability to go and uninstall all the bloat wares that some phones come pre intalled with these applications are their sponsors and they don't want that. so basically they don't trust an average user",
"There is also a question of security on a rooted device. I've got a rooted 'Droid tablet that I can do anything on but certain apps are aware of the root access. For example, on my phone I use Android pay which does not work on rooted devices because it considers the device insecure"
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6oxi0x | How were the transatlantic network cables put in place? | Were they just dropped in the water with heavy weights? How could one be sure that they ended up in the "correct" position? How deep are they usually? If a cable breaks, how to you repair/replace it? | Technology | explainlikeimfive | {
"a_id": [
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"With a really big cable laying ship. There's no need for weighing them down. The cables are quite heavy by themselves. If a cable breaks a specialty cable laying an maintenance ship goes out, finds the break, brings up the cable, and repairs it or splices in a new cable section.",
"[Modern Marvels] ( URL_0 ) had a really good episode about this!"
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6oxm89 | Why do windows updates take so long? | How can windows updates take so extremely long to install? Even accounting for time to restart services and making backups and what-not, it just doesn't make sense to me that updating the machine takes longer than installing it from scratch. | Technology | explainlikeimfive | {
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"Pretty sure it's to do with everything surrounding installing it. Installing a video game is easy because you are really just moving data around to certain locations and storing it. But if you are updating the system itself, sometimes parts that you need to install the update are What's being updated and replaced. So there's an added level of complexity. Plus, I'm sure there's different ways to do it and os makers choose the safest way and sacrifice speed to avoid potential problems. Also, I think that upon completing the process the machine does an additional step to verify that everything was done correctly which also adds time."
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6oz1cq | Why do colors look different through our phone's camera compared to our eyes? | But higher quality cameras look more like what we see in our eyes? | Technology | explainlikeimfive | {
"a_id": [
"dkll01a",
"dkmf8cz"
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"text": [
"You've essentially explained it for yourself. The higher the resolution of the camera, the more 'lifelike' (or what we perceive as such) the photo looks as our eyes are very sensitive and can pick up on details a regular smart phone camera simply could not.",
"Because our eye can see a higher color range than a standard camera sensor. The better and more expensive the camera sensor is the closer it comes to our eye. The same is also valid for the display and the printouts"
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6p0hv8 | How did AMD which is a much smaller company than Intel manage to produce a competitive Ryzen CPU? | I am curious to find out how did AMD manage to pull a rabbit out of a hat and get such a competitive well priced CPU like Ryzen. It is great from a consumer perspective but I want to find out if Intel just got lazy and were caught with their pants down or if they simply are holding back on releasing a new CPU architecture that would decimate Ryzen? Intel is a much much bigger company with massive R & D budget, and a lot more resources. Besides historically with the exceptions of few periods of time they were always in the lead. So my question is how did AMD manage to achieve this, did they reverse engineer Intel CPUs? Was the technology that Intel was using become more widely available. Or did they simply get lucky? I do sincerely hope that whatever AMD did is sustainable and that they can continue to exist and remain competitive for many more decade. | Technology | explainlikeimfive | {
"a_id": [
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"The thing is that in IT you need good engnieers. If we go back to the K6-3 and K7 generation, Intel had its P3 Coppermines and wanted to develop a new CPU which was geared more towards higher Mhz figures then efficiency, And at the same time they aquired 2 companies, Nexgen and Alpha DEC, They aquired them for patents and let go most of the engnieers, which went to work for AMD. Thats how the K6-3 and the K7 lead to a period in which AMD dominated the market, The athlon series was able to out run and out price Intels Willamette, Northwood and prescott processors which were less efficient and more expensive. The thing is that this came off a period in which intel was \"coasting\" on the success of the P3, so basicaly they were improving a bit the processor, raising its speed abit and since they had no real competition, the processors from Cyrix and AMD at the time couldnt compete against the P3. And then AMD smacked them over the head with the K7. The same thing happened now. the only real competition they had was AMD. The i3, i5 and i7 had a significant performance lead over the AMD phenom chips and were able to performe around 15% better then equivalent AMD parts while consuming around 30% less power, Intel chips were running 95 watt and then 75 watt while high end processors from AMD were struggling to provide comparable performance with 120 and 145 watt TDP, and as a act of desperation AMD released a 200 watt TDP processor. So basically this gave Intel very little reason to innovate, you had series 2000, 3000, 4000... core i3/5/7 processors in which each generation would basicaly only improve slightly bumping performance around 5-10% between generations basically stagnating CPU arquitecture. so AMD started a core redesign project which allowed them to catch up. The good thing is that every time AMD catches up, Intel does a major redesign, so its very probable that the next generation core processors will bring some real innovation.",
"Your size comparison does not really work. Intel is a much bigger company and have a lot more R & D budget then AMD. However Intel does a lot more then just designing CPUs. A lot of their budget goes towards developing new techniques for silicon wafer manufacturing. However AMD outsources the manufacturing to other companies. And Intel does not only make CPUs but also graphics cards, SSDs, motherboard chipsets, network cards and a lot of other products. AMD only makes CPUs after they split out their graphics department into a separate company. So you should really compare only the CPU design team at Intel to the entire AMD company which would likely be a much closer comparison. And with regards to Ryzen it is fair to assume that Intel was caught off guard. There was a CPU war between Intel and AMD some years ago that Intel won. So they have been well complacent cutting R & D and increasing their margins. Considering that then it is no big surprise that AMD were able to come back and rekindle the CPU war. It can take years to develop an entirely new processor so unless Intel have something in the pipeline they will likely have a hard time responding. Most of their recent releases have been improvements upon their existing processors and not entirely new designs. What they could do is to enable more features on their low cost designs which might already be on the die but disabled. AMD did for example enable ECC on Ryzen but officially it is not supported because Ryzen and Epic is the same die. But what is important to note is that Intel still have the market share in servers. If you were to build a new datacenter and is in the market to buy 100,000+ CPUs in bulk would you bet on Epic or would you stay with Intel? It may be that Epic have some problems still, and it might be that some of the applications have issues running on Epic. So Intel still have plenty of time to respond to the threat against their main market."
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6p0isn | Why do we forget about all the surroundings when watching a screen? | Technology | explainlikeimfive | {
"a_id": [
"dklnt37"
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"text": [
"The surroundings are usually dark when watching a movie or similar, which limits what you can see. There's also usually not much happening in the background for you to focus on, especially compared to what you are watching/playing."
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6p0rqg | There's a finite amount of pictures a camera can take? | I might be really off here, but I'll say it anyway. Let's take a 12MP Reflex Camera for example. It has 12 megapixels, a 12 megapixel image is 4000 pixels wide and 3000 pixels tall, which gives us around 12 million pixels. Each pixel can (on average, considering it's an 8-bit pixel) assume 16,777,216 different colors. That means there are a finite number of combinations that you can have, each combination being a full 12MP image. That would be 16,777,216 x 12,000,000, which is something like 201326592000000, or ~2.01327E14, and that's obviously a lot, but also finite. What would happen when you took the 201326592000001 picture? How can a camera have a finite number of "pictures you can take"? I sat a little while thinking it out, just thought I'd share it, I'm sure someone will disprove and show me why it doesn't work like that, but regardless, I'd love to hear it. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"You've done your math incorrectly. The actual number of possible pictures is not found by multiplying but by taking the exponent (multiplying c by itself p times), written c^p. That would be 16,777,216^12,000,000 , a staggeringly large number with millions of digits.",
"There's a mistake in your calculations. If there are 12,000,000 pixels and each pixel can have one of 16,777,216 colors, then the number of possible photos isn't 16,777,216 x 12,000,000, it's 16,777,216^(12,000,000), which is 2^(288,000,000). For comparison, the number of atoms in the universe is about 10^82 which is \"only\" about 2^(272). P.S. \"Mega\" simply means \"million\". Saying \"a 12 megapixel image is 4000 pixels wide and 3000 pixels tall, which gives us around 12 million pixels\" is redundant.",
"> What would happen when you took the 201326592000001 picture? There isn't one. Those ~2E14 bitfields are the entire space of outputs the camera can produce. If you take more pictures than that, then by the [pigeonhole principle]( URL_0 ) it must be a duplicate of one you've already taken."
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6p1svs | Why is video game optimisation when porting from PC to Console or vice versa so hard to do? | Technology | explainlikeimfive | {
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"When you develop a game for a console, you naturally have the assumption that everybody is going to be using identical hardware. If you're a developer who knows how to utilize this hardware in certain parts of your game you can start to heavily optimise a game for the console you're developing it on and get significant performance benefits which either allows to game to run smoother, or you can push for more features in your game. Some simple hypothetical examples could be if a console has a lot of RAM, you can load more things into memory to help with loading times or remove loading screens during gameplay entirely. If the CPU architecture is relatively powerful compared to the GPU, you can offload more things to the CPU and allow the GPU to focus on a particular task or visa versa. You can imagine how these types of optimsations would be at the very least, very very difficult, on a PC platform with more combinations of components with vastly different architectural designs. When you're developing for a PC audience, almost no two PCs are the same. You can think about it as lots of different machines running the same software to run games, but under the hood the combination of architectures couldn't be more different from an optimisation standpoint. With this in mind, the developer COULD feasibly take stock of what's the most popular and do some optimisations around that architecture (this is a naive, arbitrary example and would never work) but this would have a knock on effect of likely making other architecture combinations suffer. Optimising on PC is VERY difficult and it ends up being a compromise of trying to get every combination possible (within reason) to a decent level of performance. Simply put, even when you're a huge studio, or a studio with a lot of funding and some talented engineers this is a constant battle in development and will continue to be until the sheer diversity of machines on the PC platform becomes more aligned. The above is if the studio developing the game is willing to even consider explicit optimisations from platform porting. Porting a game from scratch from one platform to another is usually very expensive. The ideal scenario porting from PC to console is to develop the game from scratch because you're going from a diverse range of architectures to one/a few known and tested architectures. You can code from the ground up to optimise for those platforms. Realistically however this is way too cost-inefficient in most scenarios.",
"Games are built with their launch hardware in mind. Everything gets written to specifically optimize for those launch platforms. Developers often find clever tricks to get things running just right, and those tricks may simply not be available on a new platform. Also: inputs change wildly from PC to console or vice versa. Something designed for a mouse and keyboard isn't going to just feel the same on a game pad. Game features are built for the inputs they know the launch audience will be using. A lot of this is made easier than it used to be b/c so many games are built on top of widely-used engines (Unreal, et al). Once those are up and running on a new system it becomes a lot easier to port.",
"It's not necessarily hard, but it's a lot of work. When the game is getting ready to ship, most of the team has already moved on to the next project. It is up to just a handful of people to make the port in a couple of months, while the original production lasted a year, two, or longer. If the port is just an afterthought, there are unsolved problems to figure out, like how the controls and menus will work, and what to do about the game engine only supporting a specific framerate or resolution. During production, there was a specific console or spec that the game was made to run well with. The publisher may have strict rules and milestones for performance that must be met, so the whole team is working towards them. An engine guy might ask the level designers to reorganize a large area into two smaller levels. They might need some curtains modeled to cover up a window so you can't see outside, and then a lighting artist to do a pass on the room. It's not poor Jeff's fault that the game was designed to have 45 enemies with cloth physics in a single fight scene and now the Nintendo Switch can't possibly handle that. But Jeff can't get the outfits redesigned, and reducing the amount of physics would cause all kinds of problems. So he will cry a little bit, and then just reduce the texture resolution and draw distance as little as he can get away with.",
"When you develop for one platform, you make certain assumptions that will hold true for that platform, and code accordingly. When it comes time to port to other platforms, those assumptions are no longer necessarily true, so now you have to adjust your code to account for it. The problem, is that these coding choices are often very deeply ingrained, and changing them afterwards is very difficult. This doesn't just apply for graphics and game mechanics, but also apply for seemingly simple things, like proper keyboard+mouse support."
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6p3ahg | Why do DVD menus loop so poorly? | Technology | explainlikeimfive | {
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"text": [
"In the DVD menus the DVD players have to move back to the starting point to re-read the video, and so there is a gap where it is moving the disk. sorry about my last comment i didn't quite understand what you were asking."
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6p60or | What makes power flicker instead of going off all together? | Technology | explainlikeimfive | {
"a_id": [
"dknammn"
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"text": [
"A recloser operating on the power line is more than likely the reason. A recloser is there to interrupt the voltage to clear a fault on the line ( 2 phases slapping together in high wind or a tree branch falling onto or brushing the line). The recloser will trip, interrupting service to your house, trying to clear the fault and will do this three times. On the third time the device opens for good until an electric company crew comes out to manually reset the recloser and remove the fault in the line. When it opens on the third time you will have a power outage until the crew comes out to restore power. Edit: reading this back to myself I realize it makes no sense to a five year old. Wind blows. Tree branch breaks and falls on those wires high in the sky. Gray thing on the pole opens and closes three times to try to burn the branch off the line. If the branch is still there after the third time, lights go off for good."
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6p86mb | How do school TV systems work? | My school has a TV system and plays the announcements on it every morning. The students from the 'TV production' class are the ones who report it and it's live every morning from a camera that they anchor in front of. They'll switch from the two reporters to slides about what they're speaking of to skits they've prepared. I was wondering how a broadcasting system like that works in a school and how they play and change the stuff that goes on the screen | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"You should for sure take that class. There are basically faders and computers that people operate, as well as audio people and people that push play on recordings. If you're asking this question, you're 100% guaranteed to enjoy this course as much or more than anyone else.",
"What /u/Messisick said. But the way they go \"live\" its most likely via some sort of HDMI cable that runs around the school from the main switchboard or via a wireless video signal transmitter. (They're quiet cheap you can buy something from China for less than $100). Too bad that you can't take the class anymore, sounds interesting."
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6p9546 | Considering that we are reaching the limit of how small we can make transistors, are there other ways we can improve CPUs | Technology | explainlikeimfive | {
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"text": [
"the ultimate problem we get to is that a transistor is just a switch. which when tested will give a 1 or 0 (in logic terms). at a logical level we can't get any more basic, so the question becomes could we potentially use another device to create more switches in the same amount of space, similarly to making transistors smaller. The other way we go is when we feel we've hit some sort of absolute limit. we just expand outwardly and chips become physically larger. essentially without a discovery which revolutionizes how we look at the fundamentals of logic circuits, there is very little that can really be done, beyond miniaturization and expansion. as has been mentioned in the other comment quantum computing has it's place, but unlike a standard computer they are very specialized to completely certain tasks, and are not even remotely practice.",
"We've already effectively reached that limit. Performance gains in modern processors are largely related to pipelining (running different phases of multiple instructions at one time), multi-processing (dividing processes so they can be simultaneously processed) and cacheing (a variety of clever techniques to maximize RAM throughput)."
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6p9dey | What is the significance of the domain .io and how does it differ from the other domains such as .com and .org? | Technology | explainlikeimfive | {
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"text": [
"it's the TLD (top level domain) of the British Territory in the ***I***ndian ***O***cean. Since those domains are cheap and gained some notoriety with webgames, web-dev demos and utilities ( URL_0 is great!), they're used for novelty stuff a lot. the I/O (input-output) abbreviation comes to mind too, also nice play with URL_1 ."
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6pa1qs | What purpose did modems serve before the internet? | I was born in 2000 so I'm obviously a bit too young to have any firsthand knowledge of pre-internet computing, but I've taken up an interest in certain retro tech channels like The 8-Bit Guy and I see that a lot of older computers have ports to connect modems onto them, even computers from as far back as 1981. I know the internet didn't come around until the early 90s, so what were modems used for in those days? Did they all have some equivalent to a BBS or was there some other use that I'm just not seeing? | Technology | explainlikeimfive | {
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"You could use one modem to call another. Some applications: 1. Logging into large-scale services like CompuServe. These were private services that were similar to the modern Internet, except that the transmission rates were significantly lower so it was primarily text-based. 2. Logging into private BBS's. Individuals would set up their home computers to run a BBS and others could dial in. There were also mechanisms such as FidoNet that transmitted between these BBS's to create a large-scale messaging system. 3. Logging into institutions. Your company or university probably had a dial-up line (or several) that people could use to work remotely. This would also frequently enable you to access the *actual* Internet. What you're thinking of as the 'start' of the Internet was actually the rise of consumer ISPs and WWW protocols. It actually existed as a network of various institutions long before that.",
"You could directly call up one other computer, if it also had a modem. It was kind of like setting up your own temporary internet that had just 2 computers on it, you and them.",
"The *World Wide Web* (which is the Internet as anyone born after 2000 would know it) began in the early 90s with the creation of the Domain Name Service. With DNS, you can type an address into a browser and the computer handles all the back-end things for connecting and downloading. Before that point, we **still had internet** but it was a lot more primitive. Early modems were even as simple as [A device you literally plug your phone handset into]( URL_0 ) and you'd dial a physical phone number. Your computer would then \"handshake\" with the other computer and they'd begin sending data over the analog phone line. The earliest data being sent back and forth were military and university communications. Fun fact: You may think the internet was invented in the 90s, but [the first email was sent in 1971]( URL_1 )",
"> a lot of older computers have ports to connect modems onto them Old PC's often have a 25-pin [parallel port]( URL_0 ) and a 9-pin [serial port]( URL_7 ). External modems were usually connected to the 9-pin serial port. In the mid-1990's, internal modems became popular. These were ISA (later PCI) cards that could be installed into an expansion slot inside the PC case. After the Internet became popular, internal modems were often pre-installed by PC manufacturers. Serial and parallel ports were also used for many other devices. For example, the parallel port was usually used for printers, but according to Wikipedia [here]( URL_0 #Historical_uses) the parallel port was used for copy-protection dongles, zip drives, scanners, external modems, sound cards, webcams, gamepads, joysticks, external hard disk drives and CD drives. Also according to Wikipedia, the [serial port]( URL_5 ) had a variety of uses as well. Companies, governments and universities that had large mainframe computers or UNIX \"microcomputers\" often provided modem interfaces so employees, contractors, consultants, students, etc. could work remotely. In fact the Bell 101 modem, possibly the first device which has similar functionality to a modern modem, was created to inter-connect military sites of the [SAGE air defense system]( URL_4 ). The modem was such an influential device because it allowed re-purposing the existing telephone network (designed to transmit human voice) into a data network (allowing computers to transmit data). Once PC's and modems became popular in the mid-80s, BBS's and early online services like Compuserve, Prodigy, AOL, etc. started to pop up. When the Internet went mainstream in the mid-'90s, the larger online services became ISP's, while the smaller BBS's died out. For a few years in the mid-90s, modems were the first taste of online gaming. With PC's and modems, two players in different locations could play a game such as [DOOM]( URL_3 ), [Warcraft]( URL_2 ), or [Diablo]( URL_1 ) with each other. Player 1 would set their modem to answer, Player 2 would dial Player 1's modem, and then Player 1's computer would answer. The two computers would talk to each other and transmit game data. No Internet subscription is required [1], provided both players have landline phones to plug their modems into -- and in the 1990's, almost everyone did. [1] You were limited to modem connections to the same area, unless you were okay with extra long-distance charges on your phone bill for calling numbers in a different city. [2] Unless you had multiple landlines (not common), you also tied up the phone that was probably shared by your entire family for the duration of your gaming, BBS or Internet activity."
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6pabpp | Why are Macs considered superior when it comes to editing for their CPUs when PCs have access to powerful GPUs? | Hi, I've predominantly used a PC for my work, editing video, animating, and drawing, and I'm quite familiar with CUDA hardware acceleration, the kind Nvidia's GPUs use. It's many times faster than just using a CPU, however, whenever I see an editor who uses a Mac talk about specs, they talk about how good the CPU is for editing. Is there something about the Mac that makes the CPU better for editing, or is it just bias? Edit: Clarified a point about CUDA | Technology | explainlikeimfive | {
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"text": [
"It's not considered superior, it's just a preference, much like how people have a preference for PS4 or Xbox One. Mac DOES have reeeeaaally good edited programs, to be fair",
"This is largely a cultural thing in the design and digital media production industry, though it stems from Apple's former support for professional editing with software like Final Cut Pro and video compression standards like PRORES that made editing much easier in the 00s. The sleek design of Apple computers also contributed to why artsy hipster studios liked having them around. These days, Apple has entirely done away with Final Cut Pro, they have stripped their macs of inputs, upgradability, and have skyrocketed in price. They have focused on tiny cases which shove everything together and get hot as fuck. They have tied much of their media usage up in the disaster that is iTunes. Cineform and other compression standards are now as good as PRORES. Adobe software suite has overtaken the industry and it is identical on Windows machines. Overall, all of the strengths Macs had are a thing of the past. But the culture persists.",
"Now it's just preference. Old school Apple systems used a different CPU architecture that was faster than their Intel equivalent processors of the day. Look up the difference between RISC and CISC. They performed very well for simple parallel operations like photo and video editing. Add that too a great interface design and well done, artistic, contemporary styling of the case and you create an image artists wanted. Photoshop evolved on the Apple platform and the pc equivalents couldn't even approach it in performance and functionality.",
"There used to be a large difference because Macs were better at processing the kind of data that editing required. This also meant that the editing programs preferred Macs since it was the best platform. Nowadays, PC processes that just as well, so it comes down to preference. The only people that say Macs are better for editing are the people that aren't up to date with the times.",
"It's more of a legacy thing than anything else: It used to be that Photoshop would run better/be more optimized for Mac than PC, back when Macs ran on a PowerPC architecture (this itself has to do with how different chipsets ran different assembly languages, and different optimizations weren't kept when that was translated to an x86 architecture); also ViewSonic (monitor manufacturer) was, for a time, a Mac partner, and had very high-resolution and high color depth (for the time) monitors, which made the coloration more vivid and accurate, particularly for print applications. As of about 10-15 years ago, though, the differences between the two from a technical standpoint have all but vanished, and what remains is insignificant to the design world.",
"At the moment Max OSX is unix based, so therefore with minimal tweaking most development tools work well on a mac as it would on a linux computer. As a developer I prefer developing in OSX. Windows is trying to compete now, because they know developers making cool stuff on windows = value to consumers."
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6pao9h | How are Asynchronous Calls Used? | Technology | explainlikeimfive | {
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"Synchronous call - I'll drop you off at the store and wait her until you come back Asynchronous call - I'll drop you off at the store and periodically check to see if you are done Most calls are synchronous because the caller usually wants something right now and can't really proceed without it. But if what the call is doing is low priority, can take a long time, or is outside the control of the system, asynchronous calls make more sense. The drawback is they require extra logic to periodically check to see if the call has completed, or if it fails to complete."
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6pbmkf | How do they shoot anti-gravity scenes for space films? | Technology | explainlikeimfive | {
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"Some space movies like \"Gravity\" and \"Apollo 13\" have actually used NASA's \"Vomit Comet\". This is a jet that flies really high up and then dives. This causes everything inside to float around as if there was no gravity (there is gravity, but you're falling at the same speed as the plane so it looks like there isn't). Other movies use wires or CG",
"Most of them are done with the actors in wiring harnesses and the wires are digitally erased in post production.",
"I don't know if this holds for all space films, but for Apollo 13, they used NASA's \"[Vomit Comet]( URL_0 )\". It's a plane that flies straight down for 30 seconds at a time."
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6pbtlb | why do printers use magenta and cyan ink instead of red and blue, which are primary colors? | Technology | explainlikeimfive | {
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"Some other great answers here, but I want to add a couple of things: First of all, the human eye is sensitive to red, green, and blue. That's what makes those colors special. There's nothing magical about those colors that make them \"primary\", it's entirely based on what the human eye sees. We sense other colors based on a combination of those receptors. So if we see pure yellow light, we perceive it as somewhere between red and green. On a computer monitor, if you mix red and green in just the right way, it's indistinguishable *to the human eye*. To a different animal, the computer monitor might look terrible! Now think about pigments. Red paint doesn't glow, it doesn't give off red light. Rather, it *absorbs* green and blue light, and reflects the red. So when mixing paints, more light is absorbed, not less. It subtracts from what's reflected to our eyes. That's why if you take the exact opposite of red, green, and blue, you can produce any color on paper. The opposite of red is cyan. The opposite of green is magenta. The opposite of blue is yellow. By mixing cyan, magenta, and yellow, you can *subtact* from white paper to get any color you want.",
"Finally something I can answer. The short answer is: you've been lied to your whole life about the primary colors. They are in fact Cyan, Magenta, and Yellow, in the context of pigments. These are the subtractive primaries. In the context of light, they are Red, Green, and Blue. these are the additive primaries. That's why the pixels on your monitor are red, green and blue, but on your printer, the ink is a mixture of cyan, magenta, and yellow. your monitor is producing a colored pixel by adding the three primaries together in different combinations. your printer is producing a colored dot on paper by absorbing various combinations of these same primaries. Essentially, CMY is the inverse of RGB, and you can visualize it by understanding this -- ink \"produces\" colors by absorbing certain light and reflecting others, while a monitor simply emits a combination of primary colors. Your monitor is black until some colors are lit up. your paper is white (it reflects all wavelengths) until certain colors are absorbed (certain wavelengths are prevented from being reflected). In order to produce a red color, your printer mixes magenta and yellow pigments. This is because the magenta ink absorbs green light, while the yellow ink absorbs blue light, leaving only red light to be reflected to your eye. Similarly, cyan and yellow produce green because the cyan absorbs the red while the yellow absorbs blue. you can work out the rest for yourself. You can think of the different colored inks as different filters. If you mix all three inks together they will filter out all three of the additive primary colors, producing a black dot of ink. (of course your $100 printer is not always perfect, and mixing CMY together is a waste of expensive ink, so there is almost always a black cartridge called the key color -- that's the K in CMYK.) Basically you've been taught a dumbed down version of what the primary colors are since you were a toddler learning to finger paint. the people who made your printer know the real truth.",
"Red, Blue and Green are \"additive\" colours, meaning if you mix them perfectly you get white. Paper is already white, so it doesn't work as well. Cyan, Magenta and Yellow are \"subtractive\" colours meaning if you mix them perfectly you get black, it's almost impossible to mix them perfectly though so a different ink is used for black. You save a lot more ink subtracting from white on already white paper .",
"Cyan, magenta, and yellow are the most used subtractive primaries. Black is usually used to improve contrast and save ink. Red, green, and blue are the most popular additive primaries.",
"CMYK produces the largest color gamut while remaining efficient at only 4 colors on pretty much all presses. Color gamut is the area a press can reproduce of a LAB value chart (color chart) If you were to look at the color gamut of RGB vs. the color gamut of CMYK, you would understand why. Then look at the color gamut of OGCMYKV (Orange, Green, Cyan, Magenta, Yellow, Black, Violet) for an even larger color gamut. Depending on the color accuracy the client needs, you can pick the best process for the job. CMYK will satisfy most clients."
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6pefk9 | What stopped the internet during its inception to turn into how cable TV was? | What I mean is if you want TV channels regardless of provider you need to pay per channel or for certain packages. When the Internet came about why didn't the same happen to it? Was it because there weren't major websites/TV companies getting involved with websites? Was there regulation in place? Side question I just thought of incase someone also wants to answer: net neutrality was only passed in 2015 or so I believe? Was there legislation before that prevented ISPs from throttling the connection/fast lanes etc? | Technology | explainlikeimfive | {
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"Firstly it is important to know that originally the internet was created by the US government, called DARPA net as a way for scientists to communicate during the cold war. the biggest strength of DARPA net was that if one node was destroyed, then information could still flow to the rest of the network, useful in a nuclear war. as such the core backbone of the internet wasnt really in a position to be monetized later in the 90's the world wide web started to be a thing. it was mostly seen as a fad, as you could only use it when nobody was on a call, so clearly it would never catch on. it took forever to load simple images and other than sending mail to people, why would you ever use it? as such it was largely ignored and besides, you still needed a phone line to use it. and even then you couldnt find anything because the best search engines at the time like yahoo took forever and were trash. and then all these new \"websites\" who thought they could make money crashed and burned. hah, losers, told you the internet was a fad, there's no way you'd ever turn a profit from it. (dot com bubble) then cable internet became a thing, but hey, you still needed a cable plan. and then google became a thing and then social media became a thing. and then mainstream video hosting sites like youtube became a thing and while that was happening, there was this crappy little company called netflix who mailed out these things called DVDs. it was such a terrible idea that Blockbuster, the biggest movie rental chain in the country passed on such a stupid idea... until it became a thing and then that thing became a bigger thing when they let you stream the movies. by the way, they got the rights to show a lot of shows and movies. and now speeds are fast enough that you can watch videos, stream movies, and oh wow, that stupid gaming past time for kids is now really popular and lets you use the internet to play with other people aaaaand now it's 2015. all the older cable companies are trying to play catchup while their empires are replaced by new ones and they crumble. as a result of everyone ignoring the internet as a fad, people grow used to the idea of free sharing of information. landlines are gone as a result of smart phones so the phone companies cant really control you so it's down the the ISPs, who are the cable providers mentioned earlier to try and control what you watch. because if they can stop you from using netflix and youtube, they will try to convince you to watch THEIR proprietary streaming and video services because THEY arent slowed down. and dont worry, it's really cheap with a bundle for a cable box. TLDR: older companies dismissed the internet as a fad until it was too late, now they are trying to stay afloat by ruining the internet",
"There was! Companies like AOL and CompuServe had their own walled content exclusive to their members. However the open web started to flourish and got both bigger and better than the curated content. It is much cheaper and easier to broadcast on the web than on TV. No license deals, access rights, minimal infrastructure etc which is why the same didn't happen for TV. I'll be out of the side question. I'm outside the US and I think you want a US viewpoint on that",
"The internet was never designed to be a thing for either consumers *OR* businesses to use. The early internet was a strange collection of military and university networks. As it was something only of interest to computer geeks and other academics at that time, there was no benefit to creating separate paid-for parts of the internet. In fact in the usual tradition of academia, the core protocols behind the internet were freely published so that anyone with the necessary skills could connect up their computers to the system. And they did so bit by bit and gradually it began to become a global network of networks. Later, when the world wide web was invented, that also arose out of research/academia. This time it was at CERN, the European physics research site where international collaboration between researchers was commonplace. The inventor of the WWW, Tim Berners-Lee, actually argued with his bosses that the web should be free and open to everyone, as that would aid the collaboration and international research which CERN relies upon. In later years, as the popularity of the internet and the web has risen, there have been attempts to monetise and commercialise parts of it. But because the core protocols and principles have already been published and made available, they can be followed by anyone, which makes it very hard to turn something that's open and freely-available into a private system."
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6pghab | What happens in the background when you click on the 'Safe to remove hardware' button in Windows? | And is it important that one does that before ejecting a drive? I have seen people who just yank their USB drives off their CPU once they're done without 'safely removing it'. And that doesn't seem to harm the drive or the computer. So what does that 'safe to remove button' really do? | Technology | explainlikeimfive | {
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"The safe removal function instructs the operating system to wait for all processes accessing a filesystem to finish and then \"dismounts\" the filesystem, preventing further read/write operations. If this step is not taken, there is potential for read/write operations that have not completed or are waiting to fail, which has the potential to cause data loss.",
"Windows ensures that all writes have finished and there isn't something still in a buffer that has half written to the memory. If it loses power in the middle of a write it corrupts that block, if it loses power while writing to it's table of contents it corrupts the whole drive",
"As far as I can tell, it checks to make sure that no applications are writing to the drive, and stops new writes to the drive, before flagging the device as \"safe to remove\" and continuing to halt writes to it until you remove it."
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6phcn5 | How Do Cell Phone Towers Connect to the Network? | Recently went up north and would lose and regain reception as I drove down the highway. I'm assuming this was based on my distance to the nearest tower. This led me to wonder how the towers themselves connect to the phone network. Are they wired in? A lot of these towers looked like they were in pretty remote locations. Are they connected by satellite? Or does a tower send signals to the nearest tower until a wired tower is finally hit? | Technology | explainlikeimfive | {
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"It varies - satellite has too much latency, the actual time delays induced by satellite connections would cause problems with the timing. There are really two options - either a wired connection, or a point-to-point microwave, where the backhaul network is daisy chained off one or more upstream sites; you can sometimes recognise these wirelessly-linked sites by the presence of a small white microwave dish. It's not uncommon for sites with the microwave link to be knocked out of service when a tree grows or someone constructs a building in the middle of the link, either needing the tree to be cut back or for the link to be replanned. If there's a daisy chain with multiple sites, a link failure higher up in the chain can knock several sites out."
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