eli5: What are glitches and how do they happen?
In: 0
On what type of device or software?
Glitch is very general for “temporary error”. Depending on wich field we’re talking about they can have very different reasons. Very often it’s some timing mistake that ends up misaligning stuff
A glitch is when a piece of technology, usually a computing device, does not work as intended. The two main causes of glitches are:
-Physical interference: Broken machine, corrupted data, power surge, cosmic rays, etc. Computers are still fundamentally physical systems. They can’t tolerate extreme environments, last forever, or work perfectly all the time.
-Flawed software: There is a mistake or defect in the computer program that leads to something other than what the programmer intended. This is often called a “bug” (even though the original inspiration – a literal bug that was interfering with the operation of an old computer – fits better into the above category)
Assuming we’re talking computing, a “glitch” usually occurs when a certain sequence of information is expected, but a different set of information happens. Whether it be receiving, writing, whatever, some amount of incorrect data happens.
So to speak of a few specific glitches we might see in our daily lives, a graphical glitch can occur when the monitor expects, say, <draw red on the left, green in the middle, and blue on the right at this brightness> but receives <what the hell is a left, draw red in the middle, draw blue on the right, draw green… Somewhere off screen? Uhh… Where am I supposed to put this brightness data?> With all of those draw commands shifted one over you might have anything from a strangely colored image to graphical garbage.
Of course in computers, this would be more seen as <1,1,1,1> to use a decimal 1 to 0 range. if we’re talking about a single pixel, that is full red, full green, full blue,with full brightness or just a white pixel. If you shift those to be <0,1,1,1> the last 8-bit set gets lost and now you’re only drawing green and blue at full brightness. Whether the data just didn’t send or, as suggested in the example, got sent incorrectly, you get a temporary, unexpected effect. A glitch!
Since everything in a computer is binary – that is off or on, 0 or 1 – if a 1 appears where a 0 is expected or a 0 at a 1, that can be all it takes to cause data to misalign and have something funky happen.
In one example of numerical glitching, devices use numerical representations but they can be approximations. Am example of that is the so-called floating point format used to represent scientific numbers with two parts, a mantissa and an exponent, so indecimal terms we can talk about 5×10^2 for the value 500. This is very useful because it can contain big or small numbers.
The complication is that it is an approximation. Also the computer is rarely using decimal notation so the number becomes a binary number raised to a power of two. Small errors creep on that can quickly disappear or they can be noticeable.
Neil explains why and how cosmic rays can and have occasionally caused certifiable computer errors. Bugs, human error, and data incompatibilities are always more likely though. https://youtu.be/AaZ_RSt0KP8
Latest Answers