The full form of ROM is Read Only Memory. ROM is that part of computer memory where the data has been pre-recorded. Once you write any data into the chip of the ROM, you can’t remove it and can only read it. ROM is able to retain the present content, even if someone turns the computer off. It is an example of non-volatile memory. The personal computers that we use at our houses consist of ROM in a small amount. Several critical programs that help to boot the computer are stored in this portion of ROM. ROMs are also used in peripheral devices such as laser printers, calculators, etc. The fonts of these devices are stored in the ROM. Programmable Read only Memory (PROM) is a variation of ROM. They are blank chips where one can write data easily.