Read Only Memory (ROM)

 Read Only Memory:

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

        ROM stored data and instructions permanently. Therefore ROM is called non-volatile memory.

The information in ROM is stored by the manufacturer. ROM contains a small set of instructions called ROM BIOS. BIOS stands for basic input, output system. 

 

Types of  ROM: 

                              Different types of ROM are as follow:

PROM:

                PROM  stands for programmable read only memory. The user or manufacturer can write data and programs on it using special devices. it is typically used in electronic machines to store some information permanently.

EPROM : 

                     EPROM   stands for Erasable programmable read only memory. The user can write data and programs on it using special devices. The data and programs write on it can be erased using ultraviolet light. The ROM than can be reprogrammed.

EEPROM: 

                    EEPROM  stands for electronically erasable program able read only memory. in this memory user can erase and write instructions with the help of electronic pulses. The data can be written to EEPROM multiple times. The contents of EEPROM can be updated without removing it form the circuit board.

Different between RAM and ROM:

                                                                             The difference between RAM and ROM is as follow:

RAM:

1.     RAM is a temporary memory.
2. The data can be read and written to RAM and can be changed or deleted. 
3. Instructions in RAM change continuously as new programs executed and new data is processed. 
4. When the power is turned off all the programs So RAM is a volatile memory.

The instructions are written into the RAM at the of execution.

ROM:

1. ROM is permanent memory. 
2. The instructions written in ROM can only be new instruction cannot be changed or deleted.
3. It is not possible to write new information or new instructions into the ROM so ROM is non-volatile memory. 
4. When the power is turned off the instructions stored in ROM are not lost therefore ROM is non- volatile memory. 
5. The instructions are written into ROM at manufacturing. 

                    Difference Between PROM and EPROM:

                                      coming soon............