Operating Systems · Chapter 11

Interrupt, DMA & I/O Flow Visualizer

Compare how polling, interrupt-driven I/O, and DMA move data while consuming different amounts of CPU attention.

I/O method Transfer size Device latency Direction

System Components

CPUissues commands, handles interrupts, may copy data

Device Controllermediates access to the hardware device

Main Memorysource or destination of transferred data

I/O Devicedisk, NIC, keyboard, sensor, etc.

Step0

CPU busy units0

Data moved0

Interrupts0

Flow Timeline

Event Log

Concept Guide

Polling: the CPU repeatedly checks device status. Simple, but wastes CPU cycles while the device is not ready.

Interrupt-driven I/O: the CPU starts the operation and continues other work. The controller interrupts the CPU when service is required.

DMA: the CPU configures a DMA transfer, then a controller moves blocks directly between memory and the device. The CPU is usually interrupted only when the transfer completes.

This is a conceptual simulator rather than a cycle-accurate hardware model. Its purpose is to make control flow and CPU involvement visible.