Notes / University Notes / Operating System / Chapter 13: IO System

Chapter 13: IO System

Created: 2025-12-16Updated: 2025-12-16

How the CPU reaches a device at all — addressing it, synchronising with it, and moving the data without doing the copying itself.

I/O Hardware

port: connection point between I/O device and the host (e.g. USB, Thunderbolt)
bus: set of wires and a protocol for messages (e.g. PCI, SCSI, SATA)
controller: electronics that operate a port, bus, and device (e.g. SCSI controller)
- controller can has its own processor and memory
PC Bus Structure
- Northbridge (Memory Controller Hub): Connects high-speed devices
  - CPU, RAM, Graphics Card (AGP/PCIe)
- Southbridge (I/O Controller Hub): Connects low-speed devices
  - PCI, SATA, USB, Audio, Network...