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Foundations, lesson 1

How a computer works

Every computer, from a phone to a server, has the same main parts:

  • CPU (processor): follows instructions, billions per second.
  • Memory (RAM): fast, short-term space for whatever is running right now. Cleared when the power goes off.
  • Storage (SSD or hard drive): where files and programs are kept, even with the power off.
  • Bits and bytes: everything is stored as 0s and 1s (bits). 8 bits make a byte.

When you open a program, it is copied from storage into memory, and the CPU runs it from there.

Check yourself

1. Which part actually runs a program's instructions?

2. Where does a saved file stay when the computer is switched off?

3. What is RAM used for?

4. How many bits are in one byte?

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