Primary Memory (RAM and ROM)

This lesson covers the two types of primary memory — RAM and ROM — their characteristics, differences, and roles within a computer system. This is a core topic in AQA and OCR GCSE Computer Science.

---

What Is Primary Memory?

Primary memory (also called main memory or internal memory) is memory that the CPU can access directly. It is connected to the CPU via the system bus and is used to store data and instructions that are currently being used or about to be used.

There are two types of primary memory:

1. RAM (Random Access Memory)
2. ROM (Read-Only Memory)

---

RAM (Random Access Memory)

What Is RAM?

RAM is the main working memory of a computer. When you open a program, the operating system loads it from secondary storage (such as a hard drive or SSD) into RAM so that the CPU can access it quickly.

Key Characteristics of RAM