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Primary Storage (Main Memory)

What is primary storage?

Primary storage (main memory) refers to memory directly accessible by the CPU, used to store data and instructions temporarily or permanently.

RAM (Random Access Memory)

- Volatile memory — data is lost when power is turned off. - Stores data and instructions currently in use. - Allows the CPU to quickly access running programs and open files.

ROM (Read-Only Memory)

  • Non-volatile memory, meaning it retains data even when power is off

  • Stores bootstrap/boot-up instructions and the BIOS (basic input output system)

  • Cannot normally be changed by the user

Characteristics of RAM vs ROM

Feature

RAM

ROM

Volatility

Volatile

Non-volatile

Purpose

Stores programs/data in use

Stores boot-up/start-up code

Editable

Read/write

Read-only (usually)


Practise exam question

Describe the difference between RAM and ROM, including one example of what each stores. (4 marks)

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