Where is the program for handling interrupts i.e. interrupt handler stored?

Question

So I am studying computer organization and I came across this term interrupt handler .Do we have to install this program and where is it stored ?

Answer 1

Interrupt handlers are stored in memory, like all executable code has to be.

In a full multi-tasking OS, it's in the kernel.

Under something like DOS, programs could "terminate and stay resident", leaving their interrupt handlers hooked into the interrupt table. Multi-tasking OSes provide interfaces for programs to run in the background, and of course can't let un-trusted programs hook interrupts.