IGCSE ICT 0417 - Types and Components of Computer Systems

Objective: Know and understand the differences between ROM and RAM

Introduction

Computer systems utilize various types of memory to store and retrieve information. Two fundamental types of memory are Read-Only Memory (ROM) and Random Access Memory (RAM). Understanding their differences is crucial for comprehending how computers function.

Read-Only Memory (ROM)

ROM is a type of memory that stores data permanently or semi-permanently. The data in ROM is typically written during the manufacturing process and cannot be easily altered or erased by the user.

Characteristics of ROM:

• Non-volatile: Data is retained even when the power is turned off.
• Read-only: Primarily used for storing instructions that the computer needs to start up.
• Permanent or semi-permanent: Data is difficult or impossible to change.
• Examples: BIOS (Basic Input/Output System) in a computer, firmware in embedded systems.

Random Access Memory (RAM)

RAM is a type of volatile memory that stores data that the computer is actively using. It allows the computer to quickly access any data stored in it.

Characteristics of RAM:

• Volatile: Data is lost when the power is turned off.
• Random Access: Data can be accessed in any order, providing fast retrieval.
• Used for active processes: Stores the operating system, applications, and data currently being used.
• Examples: Used for running applications, opening documents, and general computer operations.

Key Differences Between ROM and RAM

The following table summarizes the key differences between ROM and RAM:

Feature	ROM	RAM
Volatility	Non-volatile	Volatile
Read/Write	Read-only (primarily)	Read and Write
Data Retention	Data retained even without power	Data lost without power
Speed	Generally slower	Generally faster
Cost	Generally cheaper per bit	Generally more expensive per bit
Usage	Stores startup instructions (e.g., BIOS)	Stores operating system, applications, and data in use

Summary

In conclusion, ROM and RAM serve distinct purposes in a computer system. ROM provides permanent storage for essential startup instructions, while RAM offers fast, temporary storage for active data and processes. Understanding these differences is fundamental to understanding how a computer operates.