What mechanism suspends a program's execution due to an external event, allowing it to resume later?

What mechanism suspends a program's execution due to an external event, allowing it to resume later?

• A. Interrupt
• B. Memory Manager
• C. Multi-processing
• D. Data Bus

Answer: (A)

An interrupt is a signal from hardware or software that temporarily halts the currently running program to handle an event, and then lets the program resume. When an interrupt arrives, the CPU saves the current state (such as the program counter and registers), transfers control to an interrupt service routine to address the event, and after that routine finishes, restores the saved state and continues where it left off. This enables the system to respond immediately to events like a key press, a disk I/O completion, or a timer, without the CPU constantly checking for them. The memory manager handles allocating and reclaiming memory, not suspending execution for external events; multi-processing involves switching between multiple processes by a scheduler, not the specific mechanism of pausing a single program due to an external event; and the data bus is just a pathway for data transfer, not a control mechanism for suspending and resuming execution.

An interrupt is a signal from hardware or software that temporarily halts the currently running program to handle an event, and then lets the program resume. When an interrupt arrives, the CPU saves the current state (such as the program counter and registers), transfers control to an interrupt service routine to address the event, and after that routine finishes, restores the saved state and continues where it left off. This enables the system to respond immediately to events like a key press, a disk I/O completion, or a timer, without the CPU constantly checking for them. The memory manager handles allocating and reclaiming memory, not suspending execution for external events; multi-processing involves switching between multiple processes by a scheduler, not the specific mechanism of pausing a single program due to an external event; and the data bus is just a pathway for data transfer, not a control mechanism for suspending and resuming execution.