In my hardware (computer) organization course, I’ve learned that the processor (and therefore the pipeline of instructions with which it processes) gets interrupted whenever data is received from peripheral devices.
I don’t exactly know what happens when the processor gets interrupted but I venture to guess that if we were to think of the computer as a system that operates on user input (as a general-purpose computer isn’t “autonomous” per se) then whatever information we input to the general computer, it must process immediately in order to complete the task the user issues (effectively doing “useful” work; can you imagine if whenever you left click on a mouse, there is the possibility that computer responds with the message "nope, don’t care that you’re trying to open this folder, I’m busy reading through a pdf ). Hence, the interrupt gives the highest priority to information provided by the user.
Being so powerful, is there a guideline for when (and when not) to use interrupts? Are processor units the only component of a system that can be interrupted?