Hi Diva below is a link that will give a simple answer.
Hope this helps.
Source(s): Experience and wiki answers.
ROM is Read only memory. i.e data can write only once.
There two types of ROM.
The difference between ROM and PROM.
that is ROM is programmed during manufacturing it means data stored by manufacturing company.
PROM is blank memory that a user programmable memory.
user can store content on PROM.
both ROM and PROM are Read only memory
Data can write only once.
and its not possible to write so many time.
Memories of PROM and ROM are Non-volatile in nature. Its that stored informations can retain even power goes off.