Difference Between Primary Memory Storage and Secondary Memory Storage

The world has come a long way in terms of technology. Computers have made life easier in almost every aspect of our lives. But what makes it even more amazing is the fact that computers are powered by memories. Without memories, computers would be nothing more than a bunch of wires and circuits. But memories give them the power to store and process data.

Introduction to Computer Memory

Computer memory is an essential component of a computer system. It is the part of the computer where the data and instructions are stored. Without memory, a computer would not be able to store any data or instructions. Therefore, memory is essential for the functioning of a computer.

Memory is very similar to our brain because it is used to store data and instructions. Computer memory is the storage space in which data is processed and stores the instructions required for processing. Memory can be divided into two types:

  • Primary memory
  • Secondary memory

In this article, you will distinguish between primary and secondary memory and learn the following:

What is primary memory?

Primary memory, also known as main memory, is the memory that is directly accessible by the CPU. It is the first level of memory for the CPU and is used to store data and instructions that are needed for the immediate execution by the CPU. Primary memory is usually volatile, meaning that it loses its content when the power is turned off.

The primary memory is a semiconductor memory. It costs more than secondary memory. The capacity of the primary memory is very limited and is always smaller than the secondary memory.

Types of Primary Memory

There are two types of primary memory: RAM (Random Access Memory) and ROM (Read-Only Memory).

RAM (Random Access Memory)

Random access memory, also known as RAM, is commonly known as the main memory of a computer system. This is called temporary memory or cache memory. The information stored in this type of memory is lost when you turn off the power to your PC or laptop. RAM is a type of memory that can be read and written to.

ROM (read-only memory)

ROM is a persistent type of memory. The contents are not lost even if the power is turned off. The ROM information is determined by the computer manufacturer and is permanently stored at the time of manufacture and cannot be overwritten by the user. ROM, on the other hand, is a type of memory that can only be read. It is used to store data and instructions that are required for the computer to boot up.

What is secondary memory?

All secondary storage devices that can store large amounts of data are called secondary memory. Slower than primary memory. However, you can save a significant amount of data, ranging from gigabytes to terabytes. This memory is also known as backup storage or mass storage media. Secondary memory, also known as auxiliary memory, is the memory that is not directly accessible by the CPU. It is the second level of memory and is used to store data and instructions that are needed for future use. Secondary memory is usually non-volatile, meaning that it retains its content even when the power is turned off.

Types of Secondary Memory

There are many types of secondary memory, such as hard disk drives, solid-state drives, USB flash drives, optical disks, and magnetic tapes. These types of memory are used to store large amounts of data and instructions that are needed for future use.

Large capacity storage device:

Magnetic disks provide inexpensive storage and are used in both small and large computer systems.

Types of magnetic disks:


Solid state drives provide persistent flash memory. Very fast compared to hard drives. It is commonly found on mobile phones and is rapidly being adopted by PCs/laptops /Macs.

Optical drive:

This secondary storage device is for reading and writing data with the help of a laser. Optical discs can hold up to 185 TB of data.

USB drive:

It is one of the most popular types of secondary storage devices available on the market. The USB drive is removable, rewritable, and physically very small. With 1TB pen drives on the market today, the capacity of USB drives has also increased significantly.

Magnetic tape:

This is a serial access storage device that can store very large amounts of data. Usually used for backup.

Differences between Primary Memory and Secondary Memory

  • Primary memory is also known as internal memory, and secondary memory is also known as backup memory or auxiliary memory.
  • Primary memory can be accessed from the data bus, while secondary memory can be accessed from the I/O channel.
  • Primary memory data is accessed directly by the processing unit, but secondary memory data is not directly accessible by the processor.
  • Comparing the primary storage device and the secondary storage device, the primary storage device is more expensive than the secondary storage device, while the secondary storage device is cheaper than the primary storage device.
  • Distinguishing between primary and secondary memory, primary memory is both volatile and non-volatile, while secondary memory is always non-volatile.

Characteristics of Primary Memory

  • Computer cannot run without primary memory
  • This is known as the main memory.
  • Data may be lost when the power is turned off
  • Also called volatile memory
  • The working memory of the computer.
  • Primary memory is faster than secondary memory.

Characteristics of Secondary Memory

  • These are magnetic and optical memories
  • Secondary memory is called backup memory
  • Non-volatile type memory
  • Your data will be saved forever even if you turn off your computer
  • Useful for storing data on your computer
  • Machine can run without secondary memory
  • Slower than primary memory


In conclusion, primary memory and secondary memory are two types of memory that are used in computers. Primary memory is directly accessible by the CPU and is used to store data and instructions that are needed for immediate execution. Secondary memory is not directly accessible by the CPU and is used to store data and instructions that are needed for future use. Primary memory is faster but has less capacity, while secondary memory is slower but has more capacity.

Priyanka Sharma
Priyanka Sharma
I am Priyanka, currently dedicating myself entirely to writing for ournethelps.com. In my role as a writer, I am committed to producing content of exceptional quality and collaborate closely with the ONH Team to ensure the delivery of outstanding material. Outside of work, my hobbies include creating humorous videos for my Instagram, YouTube, and Facebook channels.

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