system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do people program/teach random algorithms to actually be random?
gpt
Algorithms are not at their roots random. They are predictable because an algorithm is just following a sequence of steps and following steps exactly doesn't result in random behaviour.

That said, algorithms can start with unknowable information and use that to produce random-looking data that can't be reasonably predicted without knowing that information at the start. For example: an operating system might measure how fast a spinning hard drive responds to read/write operations - a process that involves waiting for the spinning disk to line up with the drive head - down the the nanosecond and use that time as an unknowable and not reproducible value. Now you have a little piece of chaotic information available and can produce something unpredictable, and "unpredictable" is generally a satisfactory definition for "random".

So, software can't be truly "random", but it can be anywhere from difficult to nigh-impossible to predict and that's good enough.