Diiference between ROM and PROM.
ROM: It also called Read Only Memory is a Permanent Memory. The data is permanently stored and cannot be changed in Permanent ROM. This can only be read from the memory. There cannot be a write operation since the given data is programmed in the device through the manufacturer or the user. It is a Non-volatile memory. Some illustrations of ROM are pre-programmed instructions, conversion tables etc.
PROM: It also called Programmable Read Only Memory permits user to store the data. An instrument PROM programmer is utilized to store the desired data. The process utilized is opening the links at bit locations by using high current (such process is termed as burning in). Once such process has been done, then the data is permanently stored and changes in this impossible.