Difference Between Primary Memory and Secondary Memory

Difference Between Primary Memory and Secondary Memory

Computer Memory

Memory is the most important of the computer.memory is the storage location of the computer.it is used to store the data for later use.

Different kinds of memory are available.these are differentiated from each on the basis of size and storage capacity. Some memory is used to store data on a permanent basis .while some are used to saved data on a temporary basis.

Memory consists of instructions and data saved into the computer through CPU.

Types of memory

There are basically two types of memory

  1. Secondary memory
  2. Primary memory

Primary memory

Primary memory is the type of computer memory that directly accessed by CPU(Central Processing Unit).it is used to store data temporarily.it is also called volatile memory it means when power is cut off its content will be lost.

Another name of primary memory is RAM

RAM(Random Acess Memory)

RAM stands for random access memory. It is used to store data temporarily. It is a volatile memory.it is also called the working area of the computer.it is directly accessible by computer. When CPU access data from RAM, and during access, if a power failure occurs data will permanently lose that’s why it is called volatile memory

Types of RAM 

  1. DRAM
  2. SRAM
  3. MRAM

DRAM(Dynamic Random Access Memory)

DRAM stands for Dynamic Random Access memory.DRAM mostly used to store data or programs that a computer processor needs to work. This type of RAM needs electrical power to maintain its contents.CPU cannot access data while it refreshes that’s why it is very slow.it need refresh again and again.


SRAM stands for than for Static Random Access Memory.this type of RAM is faster than DRAM. It needs no electrical power to maintain its content.

CPU does not wait for any access from SRAM.


MRAM stand for magnetoresistive random access memory). This type of RAM store data in form bits using magnetic instead of electrical power.it is much faster than DRAM and SRAM. if it shows a slight change in electrical resistance when placed in a magnetic field.

Secondary Memory

Secondary memory is used to store data permanently. It is a nonvolatile memory. It means if power supply cut off, its content remains safe.it is either an external and internal memory.

Example of Secondary Memory

Hard disk

Floppy disk


Types Of Secondary Memory

ROM( Read Only Memory)

ROM stands for read-only memory. It is permanent storage. But data on ROM can only be read cannot be erased and deleted.

Types Of ROM


PROM stands for Programmable Read-Only Memory. It is used to store a large amount of data. Once we write a dta on it, it cannot be erased.this type of ROM is written once but rea many times. If there is any mistake in writing the chip will be unusable.


EPOM stands for Erasable Programmable Read-Only Memory. This type of ROM designed to recover the problems of PROM and ROM. Users can delete the data of EPROM by using ultraviolet light.


EEPROM stands for  Electrically Erasable Programmable Read-Only Memory same as  EPROM but it uses electrical beam for erasing the data of ROM.

Difference between RAM and ROM

RAM stands for Random Access Memory ROM stands for Random Access Memory
It is a temporary storage It is permanent storage.
It used to store less amount of od data It used to store a large amount of data
It is volatile memory It is non-volatile memory