What is ROM ?

What is ROM ?

                                             ROM stands for read only memory .
The instruction in rom prepare the computer  for use .These instruction can only be read but cannot be changed or
 deleted .It is not possible to write new information into the rom .

             ROM stores data and instruction permanently .When 
the power off , the instruction stored in rom are not lost .

Types of ROM 
  There are three types of Rom .
1  .>  PROM 
2  .>  EPROM   
3  .> EEPROM
         1.   PROM 
                          PROM stands for programmable read only memory .          This form of rom is initially blanks . The user can write data 
        and programs on it using special devices .
       2.
               EPROM
                                 EPROM   stands for Erasable programmable read only memory . This rom is initially blank .The user can write data using special devices .
       3.
               EEPROM
                                 EEPROM stands for Electronically Erasable read only memory .In this memory  user can erase and write instruction with the help of electric pulses.