ROM is computer memory that is used to permanently store applications and data. There are five basic types of ROM, all of which have unique characteristics and data storage capabilities within a personal computer or electronic device.
ROM is more commonly referred to as firmware or read-only memory. It is not to be confused with RAM chips, which are used to store temporary data on a computer. The five main types of ROM are ROM, PROM, EPROM, EEPROM and flash memory. Although these ROM types have different functions, all are composed of non-volatile chips that prevent data loss when there is no power fed to an electronic device. Data stored in ROM chips cannot receive modification once installed unless a special operation is used to change the data.
ROM chips consist of a grid of columns and rows. Power passes through these columns and rows with diodes designed to allow current to flow in one direction. In order for a ROM chip to function correctly, it needs to be programmed with complete data since there is no method of rewriting data on once it has been added to the ROM chip. While designing an original ROM template may require a lot trial and error, one of the main benefits of using ROM chips is that the chips are very cheap and extremely reliable in most electronic devices.