Computer studies Made Simple : Types of Computer Memory

Types of Memory:

Memory has two types:

1.RAM

2.ROM

1.RAM / Random access memory:

Also known as Direct Access Memory

In this type of memory,each individual byte in entire memory canbe accessed directly.

This is a temporary memory.

When the power is turned off,all the information in the RAM is lost.

It is also called as volatile memory.

CPU can read data from RAM and write data to RAM as well.

RAM is also called as read write memory.

It is used to store data and instruction while it is being executed.

RAM is also called as Main Memory or primary storage.

2.ROM/Read Only Memory:

The instructions I ROM prepare the computer for use.

These instructions can only be read but cant be altered or deleted.

It isnot possible to write new information or instructions into the ROM.

ROM stores data and instructions permanently.

When the power is turned off,the memory in ROM isnot lost and hence is called as non-volatile memory.

The information on ROM is stored by manufacturer and hence,when the power is switched on,the instructions in ROM are loaded into the memory of computer.  

Types Of RAM

RAM is built by using two different techniques:

A.      DRAM :

DRAM / Dynamic Random Access Memory:

This type of memory is used in most computers.

It is most economic type of RAM.

It requires an electric current to maintain its electric state.

The electric charge on DRAM decreases with time and this may result in loss of data.

DRAM has to be recharged over and over again to maintain its data retaining capabilities.

It has slower performance because the processor cannot acces its data while its being recharged.

B.      SRAM

SRAM /Static Random Access Memory :

The memory cells are made from digital gates.

Each cell can store its value without any read to refresh the data as long as the power is available.

SRAM is relatively more expensive.

CPU can access data readily as it doesnot need to be recharged to maintain its performance,hence its faster.

It uses more power than DRAM and canbe used to build a very fast emory called as Cache memory