ROM is an acronym for Read-Only Memory. A computer needs two types of memory- static and dynamic:
ROM: doesn’t change and can only read from it. It can’t be written over or “updated” with new information without erasing the existing data in ROM, but is semi-permanent storage that cannot be deleted even if electrical power is lost
RAM: often short-term memory representations of what was on the CPU when something interesting happens. This means that volatile physical material must exist in RAM for your computer to process what you are doing – it’s all or nothing, meaning that everything currently in RAM will be lost should a power outage occur.