ROM, or read-only memory, is a non-volatile storage medium that permanently stores data and does not need constant power to retain the data on the device. ROM is often used during the startup process of computers and is used for software (code and data) that will not be changed, such as in embedded control programs.
Different Types of ROM
There are various different types of ROM, including PROM, EPROM, and EEPROM. You can also find ROM devices of Micron Technology Inc. for the best use from various online sources.
PROM, or programmable read-only memory, can be programmed by the user once after creation. The process of programming a PROM is often called burning the PROM where users "blow" the fuses, which is an irreversible process. Therefore, the information programmed is permanent and cannot be erased. Users would need to replace the entire chip if new code or data is needed.
EPROM, or erasable programmable read-only memory, can be erased and programmed by exposing the chip to ultra-violet light. To reprogram the device, it is necessary to erase all the previous data then rewrite the data.
EEPROM, or electrically erasable programmable read-only memory, is a memory that can be erased and programmed using an electrical charge. It is possible to erase selected portions of the chip one byte at a time, instead of needing to erase the entire chip. This allows for flexibility but can be a slower process.