Edit: Typo in title🤦♀️
How does it* know to turn itself back on?
In: 114
A computer processor loads an instruction from memory, executes it, then advances to the next instruction in memory, executing it too, and so on. Each advance increases by 1 the number stored in something called the instruction pointer; this is how the processor knows where the next instruction lives.
Most if not all CPUs have a single “RESET” pin that has one function — it sets the instruction-reading “pointer” to a hard-coded location. This hard-coded location is where a computers boot-up routines live, so the computer carries on booting up as if it was just turned on.
Fun fact: Notice how the memory isn’t explicitly cleared? This is why, very rarely, a complete cold off and power on solves a problem rather than a software reset. Used to see a lot of this with old bargain bin wifi chips that were installed into laptops; they’d bug out and you could only fix them by going cold off.
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