The Actual Difference Between RAM and ROM Explained

Difference Between RAM(Random Access Memory) and ROM(Read Only Memory)

Difference Between RAM and ROM, RAM VS ROM

The actual difference between RAM and ROM is that the RAM can store data temporarily but ROM can store data permanently. The CPU can access data of the RAM randomly but the CPU can only read the data of ROM.

Many differences between RAM and ROM can be written based on size, price, and many other things but you should know what is the actual difference between RAM and ROM. I have written some unimportant differences in the below table which you can only write your exam but if you want to know the actual difference then must read the full article.

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Random Access Memory
Read Only Memory
It is a Volatile Memory.
It is a Non-Volatile Memory.
It is also called Read/Write Memory.
It is only read memory.
Processors use this memory to store data temporarily
The processor uses this memory only to read the data.
A RAM chip can store more data than a ROM chip.
A ROM chip can store a very less amount of data than RAM but remember that the data storage rating of the ROM is very much greater than RAM because a part of the secondary memory is used in ROM in the computer or Smartphones.
The processor uses RAM during the execution of programs.
The processor uses ROM only at starting time of the execution of programs.
Random Access Memory is more costly than the Read Only Memory.
Read Only Memory is less costly than Random Access Memory.
The CPU can modify the data of the RAM
The CPU cannot modify the data of the ROM
The speed of the computer or smartphone is mostly dependent upon the RAM.
The speed of the Computer or smartphone is also dependent upon the ROM but less.
A separate chip of RAM is used in computers or phones.
A separate chip of ROM is used in the computer but a part of the secondary memory is also can be used as ROM.

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Let's understand in detail,

Actually, are you know why different types of memory used in the computer? As technology going better our work also increasing. We want to complete a lot of tasks in a very short time. The computer will work fast if it has a high-speed processor as well as high-speed memory. As the cost of high-speed memory is very high we use various types of memory in the computer for different tasks. We cannot use a slow memory for all tasks, it will waste our time. We cannot use also high-speed memory for all tasks because it required a high cost.

For example, we cannot use cache memory as a storage memory to store movies, songs, etc because although cache memory is very fast but it is very costly. On the other hand, we cannot use the hard disk as RAM because although it is low cost, it is a very slow memory.

Must Read: What is Cache Memory? Explained in Detail.

Random Access Memory(RAM):

RAM is not any particular memory it is a type of memory based on the operation. For example, the hard disk can be used as RAM but as the hard disk is very slow a special type of memory chip(separate from the main storage memory) is installed in the computer which may be made by transistors or capacitors which is called RAM.

As we know that when we perform any task on the computer, at first the Processor reads the instruction then it understands what to do. Then the processor starts executing the programs. During the performing of any tasks, the processor needs some data. Sometimes the same data is required for a no. of times to perform the same task. These common data which required no. of time to perform a particular task are stored in RAM.

For example, suppose you open a web page and you read that page from the top to bottom a no. of time so in this case, at the first time the processor stores the data of that webpage in RAM, and when you scroll the page and see the page no. of time the processor provides the data from the RAM. When you close the web page the data from the RAM will be erased.

RAM is also called Volatile memory because once the power supply of the RAM is OFF all data of the RAM will be erased.

There are mainly two types of RAM,
  1. SRAM or Static Random Access Memory
  2. DRAM or Dynamic Random Access Memory
Static RAMs are mainly made by only Transistors but Dynamic RAMs are made by capacitors and transistors.

ROM(Read Only Memory):

The Read Only Memory is a type of memory from which the processor can only read the data not write the data. We already know that to perform any task the CPU first read the instruction or program then it starts execution. So from where the CPU reads, the data is called read-only memory.

As the processor can only read the data from that memory not write data that is why it is called read-only memory. But remember that there are some ROMs in which the user can write data but some ROMs in which the user cannot write data. But the Processor always can only read the data from ROM.

The ROM in which firmware is installed cannot be written by the user. The manufacturer installed the firmware(it is also a software) into the ROM. This type of ROM we can see on the computer in the form of IC.

We all know that our computer has a 'C Disk'. Disk 'C' is the part of the hard disk. But our computer use that 'C' disk as ROM. When we installed any application or software, the data of that application is stored in the 'C' disk. When we want to run that application the CPU read the data from the 'C' Disk and understands what to do. So in this case, the CPU read the data from the 'C' Disk.

In the early days of our mobile phones, we cannot install or uninstall the application. But nowadays we can install and uninstall applications anytime. Because in the early days, the mobile manufacturer installed all the applications in a ROM chip. But nowadays in smartphones, the ROM is included with our main storage memory. The processor can use that memory as ROM and we can use that memory to store movies, songs, etc. For this reason, we see in our phone in the 'About phone' section 2GB, 4GB RAM, etc, and 8GB, 16GB ROM, etc. But the RAM is always separated. A separate RAM chip is placed in the phone or computer.
But one thing remembers is that RAM always separates it never include with the main storage memory.

Types of Read Only Memory(ROM),

  1. PROM or Programmable Read Only Memory.
  2. EPROM or Erasable Programmable Read Only Memory.
  3. EEPROM or Electrically Erasable Programmable Read Only Memory.

Read Also: Operating system | All types of Operating System Explained with examples

Let's Understand the difference between RAM and ROM with an Example:

Suppose we want to write something in MS Word. When we click on the icon of MS Word the CPU start reading the data which stored in ROM and understands what to do. Then it opens MS Word. Now when we write some words in MS Word, the Words storing in RAM for temporarily. If we close the MS Word without clicking on the 'Save' option, the data will be erased. But after writing some words if we click on 'Save', the data will be stored in Hard Disk or other Storage memory for permanently.


So, we can say the difference between the RAM and ROM is that the CPU use ROM to understand what to do and use the RAM to store data temporarily during execution time.

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The Actual Difference Between RAM and ROM Explained The Actual Difference Between RAM and ROM Explained Reviewed by Author on January 12, 2019 Rating: 5
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