Computer components and embedded systems
What's inside a computer
- Every general-purpose computer is built from the same four blocks.
- Understanding them explains how a program runs.
- We finish with embedded systems — computers hidden inside other devices.
Input and output devices
- Input devices get data in: keyboard, mouse, microphone, scanner, sensors.
- Output devices give results out: monitor, speakers, printer, actuators.
- Input → processing → output is the basic flow of any computer task.
Practice
Which of these is an input device?
A scanner brings data in. Monitors, speakers and printers are output devices.
Memory and storage
- Primary memory is fast memory the processor reaches directly — RAM and ROM. It holds the running program and its data.
- Secondary storage is slower but larger and keeps data without power — hard disk, SSD, optical disc, USB stick.
- The CPU can't run a program straight from secondary storage — it is loaded into primary memory first.
Practice
Match each part to its category.
Keyboard = input, monitor = output, RAM = fast primary memory, SSD = non-volatile secondary storage.
Practice
Primary memory differs from secondary storage because it:
Primary memory (RAM/ROM) is fast and directly accessible by the CPU; secondary storage is slower, larger and non-volatile.
Embedded systems
- An embedded system is a computer built into another device to do one fixed job (washing machine, microwave, car engine unit, thermostat).
- Benefits: optimised for one task (low power, small, cheap), reliable, fast to start.
- Drawbacks: limited to that one task, hard to update (special tools for its firmware), often not repairable, sometimes weak security.
Practice
An embedded system is:
Embedded systems (in a washing machine, microwave, car…) are dedicated to a single fixed task.
Practice
A drawback of an embedded system is that it:
Being dedicated makes it efficient but inflexible — it cannot easily be repurposed and its firmware is hard to update.
You've got it
Key idea
- four blocks: input, output, primary memory, secondary storage
- primary (RAM/ROM) = fast, CPU-direct, holds the running program
- secondary = slower, larger, non-volatile (HDD/SSD/optical/USB)
- an embedded system = a computer built into a device for one fixed job