Different types of ROM: MROM, PROM, EPROM, EEPROM

Different types of ROM: 

Primary memory is the main area in a computer in which data is stored for quick access by the computer’s processor.
ROM (Read Only Memory) is a type of primary memory. It is a non-volatile memory chip, in which data is stored permanently and cannot be altered by the programmer. 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).
There are four types of ROM:

1. MROM (mask ROM)
2. PROM (programmable ROM)
3. EPROM (erasable programmable ROM)
4. EEPROM (electrically erasable programmable ROM)

MROM: 

MROM (mask ROM) is manufacturer-Programmed ROM in which data is burnt in by the manufacturer of the electronic equipment in which it is used and it is not possible for a user to modify programs or data stored inside the ROM chip.

PROM: 

PROM (programmable ROM) is one in which the user can load and store “read-only” programs and data. In PROM the programs or data are stored only fast time and the stored data cannot modify the user.

EPROM: 

EPROM (erasable programmable ROM) is one in which is possible to erase information stored in an EPROM chip and the chip can be reprogrammed to store new information. When an EPROM is in use, information stored in it can only be “read” and the information remains in the chip until it is erased.

EEPROM:

 EEPROM (electrically erasable programmable ROM) is one type of EPROM in which the stored information is erased by using high voltage electric pulse. It is easier to alter information stored in an EEPROM chip.