What Is A Primary Storage Device?

Date First Published: 6th March 2024

Topic: Computer Systems

Subtopic: Computer Hardware

Article Type: Computer Terms & Definitions

Difficulty: Medium

Difficulty Level: 5/10

CONTENTS

Examples Of Primary Storage
Difference Between Primary Storage and Secondary Storage

Learn about what a primary storage device is in this article.

Primary storage is a type of data storage that is directly accessible by the CPU. It is smaller in size than secondary storage and is a key component of a computer for it to function. Primary storage is used to hold data, programs, and instructions that are currently in use.

Since primary storage is located on the motherboard, data can be read from and written to very quickly, much more quickly than secondary storage that is not always directly accessible by a computer. The data is usually volatile, meaning that it is lost when the system is powered off.

Examples Of Primary Storage

Examples of primary storage include:

ROM - A form of permanent and non-volatile memory that computers can read but not write to or remove. ROM is useful for storing software that is not expected to be changed during the lifetime of a system.
RAM - A form of volatile memory used to temporarily store data the processor is currently using so that it can be quickly reached.
Cache memory - A smaller type of volatile computer memory that provides high-speed data access to the processor and stores frequently used computer programs, applications, and data.

Difference Between Primary Storage and Secondary Storage

The main difference between primary and secondary storage is that primary storage storage is internal to the system, directly accessible by the CPU, whilst secondary storage is non-volatile, external to the system, not directly accessed by the CPU, and used to store and retrieve information in the long term.

Compared to secondary storage, primary storage (e.g. RAM, ROM, cache, and flash memory) is smaller in size and is a key component of a computer for it to function. In modern computers, primary storage is often around 4-16 GB in size, whilst secondary storage can be hundreds of gigabytes in size. Secondary storage is not necessary for the normal functioning of a computer, but is used to backup data from the primary storage.