Difference between PROM, EPROM, EEPROM

ROM is non-volatile(permanent) memory. ROM is used to store OS(Operating System) which helps us to boot(start) our computers.

ROM are of 3 types namely: PROM, EPROM and EEPROM

PROM is Programmable ROM.

It can be written only once.

Once written it cannot be modified or changed.

EPROM is Erasable Programmable ROM.

It can be modified N number of times.

We have to expose it to UV light in atmosphere and data will be erased.

But, problem is that we can’t do selective deletion i.e. when we delete need  to delete something in EPROM we need to delete everything and write all over again.

EEPROM is Electrically Erasable Programmable ROM.

In EEPROM as name suggests we have to use electricity to delete.

But, here we can delete a particular thing which we want.

Whereas, if we expose EPROM to UV rays everything is deleted and in EEPROM we can use electricity and do selective deletion.