ROM (Read- Only Memory)| What Is ROM | Definition Of ROM| Type Of ROM | ROM In Computer | ROM Computer Notes| ROM (Read- Only Memory) In Hindi

 

ROM (Read- Only Memory)

A special type of RAM, called read-only memory (ROM), is a non-volatile memory chip, in which data is stored permanently and cannot be altered by the programmer. In fact storing data permanently into this kind of memory is called “burning in the data”, because data in such memory stored by using fuse-link. Once a fuse-link is burnt, it is permanent. The data stored in a ROM chip can only be read and used-they cannot be changed. This is the reason why it is called read –only memory (ROM).

Since ROM chips are non-volatile, the data stored inside a ROM are not lost, when the power supply is switched off, unlike the case of a volatile RAM chip. ROMs are also known as filed stores, permanent stores or dead stores.

ROMs are mainly used to store program and data, which do not change and are frequently used.

Fig: ROM

Types of Read Only Memory (ROM) – 

   

      ·  PROM 

      ·    EPROM

      ·  EEPROM
 

 

1.   PROM (Programmable read-only memory) 
 

 It can be programmed by the user. Once programmed, the data and instructions in it cannot be changed. 
 

2.   EPROM (Erasable Programmable read only memory) 

 

It can be reprogrammed. To erase data from it, expose it to ultraviolet light. To reprogram it, erase all the previous data. 
 

3.   EEPROM (Electrically erasable programmable read only memory) 

 

The data can be erased by applying an electric field, with no need for ultraviolet light. We can erase only portions of the chip.