3 Types of Memory in Computer & Importance of Computer Memory

Do you know the importance of Memory, the major 3 types of memory in computers? If not then all of you have come to know about computer memory. In this post, you will get the knowledge in detail about all types of memory of computers. So let’s start without delay.

A person can remember any instruction or information in the mind for some time or a few days, but the computer is such a device that can store any information or data safely for years. Memory is an essential component of digital computers. Computer memory serves as a storage device. It stores programs, data, results, etc.

For a person, not remembering the smallest details in his mind may be a small thing, but for a computer, memory is an important thing. without it, he can’t do anything. In this article, I will give you complete information about the memory of the computer. So read this article and increase your maximum knowledge in memory topics.

Importance of Computer Memory

Computer memory is similar to the human brain. Like the human brain remembers any information, in the same way, the memory of the computer also works to store data and instructions. When that information is needed, the computer recalls it.

Computers operate and store data with binary digits 0 and 1. This binary digit is called a Bit. These bits are grouped together to form memory. If 4 bits are combined to form a word, then it is called a Nibble.

For Example- 0011,1100,1001,0110 0001, etc

            If 8 bits or 2 Nibbles together form a word, then it is called a Byte.

            For Example- 00000001, 10000000, 10000001 etc

            Today the memory has become so big that the byte unit is very small.

KB (Kilobyte)  1024 Bytes1 KB
MB (Megabyte)1024 KB1 MB
GB (Gigabyte)1024 MB1 GB
TB (Terabyte)1024 GB1 TB
EB (Exabyte)1024 PB1 EB
ZB (Zettabyte)  1024 EB1 ZB
YB (Yottabyte)1024 ZB1 YB

At present, the following three kinds of memory are commonly used in a modern computer.

  • Semiconductor memory
  • Magnetic memory
  • Optical memory

The semiconductor memory is faster, more compact, and lighter. it consumes less power. It is a static device. There is no rotating part in it. Magnetic and optical memory is slow compared to semiconductor memory. but they are cheaper than semiconductor memory. They are not static devices. They are either in the form of a rotating disk or tape.

All computers except mobile, new generation laptops, or tab, contain both semiconductors as well as magnetic memory. This memory is called the main memory (primary memory) of the computer. It stores program and data which is currently processed by the CPU.

Magnetic memory is also called auxiliary (secondary) memory. This memory stores the data or information that has already been processed for future uses.

3 Types of Memory in Computerr

There are 3 types of memory in computer.

  • Cache memory
  • Primary memory
  • Secondary memory

Cache memory

Cache memory is placed between the CPU and the main memory. It is a semiconductor memory. Its access time is about 10ns, which is much less than the main memory. It stores frequently used data or information, which is required by the Central Processing Unit during the processing time.

A microprocessor chip is used in the cache memory. The operating speed of modern microprocessors of 32-bit and 64-bit is much higher. Their clock speed ranges from 400 MHz to 1000 MHz. The memory to match the high-speed microprocessor is much faster, so its cost is also high.

If the microprocessor will work with the main memory, then it will have to work slowly. This will reduce the speed of the computer. Therefore high-speed cache memory only sends the currently running programs and instructions to the CPU. The Main memory stores those programs that are executed by the CPU.

Advantages of cache memory

  • The cache is much faster than all memory.
  • In this, frequently used programs and instructions are stored.
  • it is accessed the data very shortly and executed it.

Disadvantages of Cache memory

  • Its storage capacity is limited.
  • This memory would be expensive.

Primary memory

Generally, primary memory is an essential component of a computer. So without this memory, the computer would not even start. Whereas this memory helps in booting the computer. Programs and data are loaded into the primary memory before processing.

The CPU directly interacts with the primary memory for read and write operations. Primary memory only contains the data that the CPU is currently processing. This memory cannot store data for a long time because its storage capacity is less.

Primary memory is 2 types

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



RAM is also called random access memory. As its name suggests, the CPU uses this memory when it accesses and processes random data from the secondary memory. RAM is used for read and write operations of data that the CPU accesses randomly.

When the computer is turned off, the data stored in RAM is automatically deleted. That’s why this types of memory in computer is also called volatile memory. Ram checks the data being processed properly and corrects the data which is wrong.

RAM is also 2 types


SRAM is called Static Random-Access Memory. The processing speed is higher due to the presence of semiconductors in this memory. This Ram does not need to be refreshed periodically as compared to other RAM. This RAM is expensive compared to other RAM.


DRAM is also called Dynamic Random Access Memory. This memory works by getting electricity and processing the data. This RAM is cheaper than the other RAM. So, it is used in laptops and desktops. and it needs to be refreshed periodically.


ROM is also called Read-Only Memory. Even after the power of the computer is switched off, the data stored in it is not lost, therefore, it is called non-volatile memory. The main function of this memory is to read the data stored inside it.


It is mounted on the motherboard of the computer. Which is called Bios IC. This IC would have been programmed. Which is helpful in booting the computer.

ROM is divided into 3 types.

  • PROM


The full form of PROM is Programmable Read-Only Memory. It can be programmed by the user. Once this memory is programmed, its program cannot be modified or erased.


The full form of EPROM is Erasable Programmable Read-Only Memory. It has a nice feature. Data stored in the EPROM can be erased, and other data can be reinserted into it. Data stored in EPROM is erased through ultraviolet light.


It is also called as Electrically Erasable Programmable Read-Only Memory. The data stored in it can be erased through electrical charges. It has a nice feature that we can delete the data we want to delete and the rest of the data remains safe.


Secondary memory is called external memory or non-volatile memory. Its main use is to store data or information permanently. Therefore, this types of memory in computer is called non-volatile memory. An advanced version of secondary memory has also arrived today. SSD is an example of this. It works much faster than the old hard disk and is smaller in size.

The CPU cannot access any data or information directly from it, so input-output routines have to be used. CPU processes data from secondary memory through RAM. Users can easily access the stored data in sequential or direct methods.           

For Example – Magnetic tape, Magnetic disk, Hard drive, SSD, CD, DVD, Pen Drive, etc

Magnetic Tape

In the olden days, magnetic tapes were used to store data. However, its use in computers ceased long ago. This was called sequential access memory. Because of this, the data was kept in a sequential manner. If this tape has 5 data and you want the 4th number of data then you have to go in sequence way and after that, you can access the 4th data.

Magnetic disk

A magnetic disk is used as the main memory in a computer. It is a thin plastic or metal circular plate coated with a magnetic oxide and also encased in a protective covering. The data is stored as magnetized spots on a magnetic disk in binary forms, such as 0s and 1s.

Hard drive


The hard drive is a major storage device in a computer. Because the operating system running the computer is stored inside it. There is a magnetic plate in it in which the data is stored. The data that we all use on the computer can also be stored on the hard drive for a long time. It is a non-volatile memory. It connects with the motherboard and processes the stored data.

Generally, the hard disk connects to the motherboard via data cables like SATA (Serial Advanced Technology Attachment), PATA (Parallel Advanced Technology Attachment), and SCSI (Small Computer System Interface).


SSD stands for Solid State Device. This is the latest drive today. SSD uses a NAND flash memory chip to store data. It is small in size but its processing speed is higher than all other storage devices. SSD is more expensive than hard drives. No data cable is used to connect it to the motherboard. It is inserted into the slot on the motherboard.



The full form of CD is Compact Disc and the full form of DVD is Digital Versatile Disc. These two are just the difference in storage capacity. CDs and DVDs have storage in the data layer. The storage capacity of CD is 695 MB while the storage capacity of DVD is 4.7 GB. CD has one layer and DVD has many layers, that’s why DVD has more storage capacity.

Floppy Disk

A Floppy disk is a secondary storage device. It is not being used anymore. Because its storage is very less. It is made of a plastic sheet called a mailer and magnetic material is glued on both its sides.


I hope that you must have liked my article “Importance of computer memory & top 3 types of memory in computer”. I have mentioned memory in detail in this article. If you have any doubts about this article or you want there should be some improvement in it, then you can comment below. We will definitely solve it.

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4 thoughts on “3 Types of Memory in Computer & Importance of Computer Memory”

  1. Thank you sir for this article, i can do revise anytime from this article.
    Hope so I could learn more about computer before my Examination. So it’s a humble request to post more about computer.

  2. Thanks a lot for the article about the Hardware components and their uses with software . It has enriched my knowledge about hardware and software and help me in understanding the computer in practical field. I would request you to provide more articles like this one to help me in future . Thanks . S .R . Biswas from India.


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