Question $1$:

$[2$ POINTS$]$

In the context of OS$,$ could you furnish a definition for the concept of interrupt?

Question $2$:

$[3$ POINTS$]$

Interrupts can be categorized into several groups according to numerous factors, including their source, priority, and the actions they trigger.

Could you please provide some elaboration on the classification mechanisms mentioned and offer illustrative examples?

Question $3$:

$[5$ POINTS$]$

In the process context switching, explain exactly how the kernel determines the size of the allocated stack over a period from the new process state until the termination state, assuming the system is utilizing a single core, with time$-$sharing principle.