C25 45 min
Computer system components
The parts of a computer system and how they work together, from CPU to input and output.
The core parts
A computer system combines hardware and software to process data.
| Component | Role |
|---|---|
| CPU | Executes instructions |
| Memory (RAM) | Holds active data and programs |
| Storage | Keeps data persistently (SSD, HDD, flash) |
| Input devices | Bring data in (sensors, keyboard, camera) |
| Output devices | Present results (display, actuator, speaker) |
| Bus / interconnect | Moves data between components |
The stored-program model
Instructions and data share memory. The CPU repeatedly fetches an instruction, decodes it, executes it, and writes results back. This fetch–decode–execute cycle is the foundation of almost every general-purpose computer.
Embedded variation
An IoT node carries the same ideas at a much smaller scale: a microcontroller, a few kilobytes of memory, flash storage, and sensors instead of keyboards. The trade-off is fixed function and low power rather than general-purpose performance.
Check your understanding
- Explain the difference between memory and storage.
- Why do embedded systems use less RAM than desktop computers?