Which of the following does not interrupt a running process?

Answer: Scheduler does not interrupt a running process.

Explanation:

• Device: Hardware devices generate interrupts (I/O interrupts) to signal events like completion or errors; these interrupts preempt the CPU and interrupt the running process so the kernel can handle the event.

• Timer: The system timer issues periodic clock interrupts used for timekeeping and for enforcing time-slicing. A timer interrupt interrupts the running process to allow the kernel to perform scheduling and accounting.

• Power Failure: A power-failure or similar emergency signal results in an immediate hardware interrupt (often non-maskable) so the system can react; this interrupts the running process to handle the critical condition.

• Scheduler: The scheduler is a software policy component that selects which process should run. It does not itself generate hardware interrupts. The scheduler runs when invoked by interrupts, exceptions, or system calls to perform a context switch, but it does not directly interrupt the CPU on its own.

Key takeaway: Interrupts are typically generated by hardware events (devices, timers, emergency signals). The scheduler is a software module that is invoked after such events to choose the next process; it does not by itself cause the interrupt.