What do we store in ROM?

Read-only memory, ROM, is usually found in computers and other electronic devices as a storage medium. Impliedly, data that are stored in ROM can only be read and it is almost impossible or even difficult to modify them. ROM is also another form of a non-volatile storage medium because the information is maintained even though the constituent drops dead. ROM is mostly used for firmware, which is also known as basic input/output system (BIOS), updates that gives instructions on how to start a computer device.

The code stored on the ROM are specific to the hardware. Sometimes, a firmware can be updated by installing an additional memory or hard disk. Read-only memory is useful for storing the software that would hardly be changed throughout the lifetime of the device. Conclusively, the read-only memory refers to the distinct memory that is hard-wired and cannot be altered after production such as the diode matrix.