RAM vs ROM explain the differences between RAM and ROM memory 


Data and programs need to be stored in a computer system. The technology used to do this is called memory. Memory can be divided into two types: main memory and secondary storage. Main memory is any memory that is directly accessed by the CPU, for example, ROM and RAM.

Definitions and features

ROM (Read Only Memory) provides the computer with instructions that do not change - such as boot setup.

RAM (Random Access Memory) is the working space in which the computer stores data in current use.

RAM and ROM both are the internal memory (main memory) of the computer. RAM is a temporary memory while ROM is a permanent memory of the computer. There are many differences between RAM and ROM, but the basic difference is that RAM is a read-write memory and the ROM is a read only memory. 

Volatile memory is computer memory that requires a power supply in order to maintain stored data. In other words, volatile memory will store information as long as power is being supplied to it. However, the moment that the power is turned off, the information is lost. Volatite memory is often referred to as 'temporary memory'.


Some differences between RAM and ROM are shown below



It is a read-write memory.

It is read only memory.
Use Used to store the data that has to be currently processed by CPU temporarily. It stores the instructions required during bootstrap of the computer (BIOS).
Stands for Random Access Memory. Read Only Memory.
Volatility It is a volatile memory. It is a non-volatile memory (permanently).
Modification Data in RAM can be modified (removable). Data in ROM can not be modified (not removable).
Capacity RAM sizes from 64 MB to 4GB. ROM is comparatively smaller than RAM.
Cost RAM is a costlier memory. ROM is comparatively cheaper than RAM.
Type Types of RAM are static RAM and dynamic RAM. Types of ROM are PROM, EPROM, EEPROM.


  1. What do the letters ROM stand for?
  2. What do the letters RAM stand for?
  3. What is the main difference between RAM and ROM?
  4. Define the term "volatile memory".
  5. Does a computer system use RAM or ROM for the temporary storage of data?
  6. Why is ROM read only? Why can't I change what it holds?
  7. Is ROM volatile? 
  8. Why is it good that ROM is non-volatile? 


Exam questions:

Which of RAM and ROM permanently holds specific functions? (Marks: 1)
  • ROM.
Access to ROM is slower than access to RAM. True or False? (Marks: 1)
  • True.
Why is important for computers to have adequate capacity of RAM? (Marks: 2)
  • A large amount of RAM enables more instructions/programs to be loaded from secondary storage into RAM (1) so they can be executed by the processor more efficiently rather than the CPU needing to wait for the instruction to be located and loaded. As a result more programs may be run simultaneously. Additionally, some programs simply need a lot of RAM to run properly (1), such as games programs.


Ex. 1 (Author: Litvinova Olga - CS teacher of NIS Pavlodar)

Ex. 2

Ex. 3

Категория: Main memory | Добавил: bzfar77 (08.09.2020)
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