I/O systems
Components enabling computers to communicate with external devices through ports, buses, and controllers. I/O systems handle keyboards, mice, displays, printers, networks, and storage. Interrupts and DMA coordinate I/O transfers.
Real World
When you plug a USB keyboard into a laptop, the I/O controller detects the device, the OS loads a driver, and each keypress triggers a hardware interrupt so the CPU processes it immediately without constantly polling the port.
Exam Focus
Clearly distinguish interrupts from polling and DMA from programmed I/O — examiners expect named advantages of each transfer method.
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