What is ROM ? Explain the different types of ROM.Ripunjay Tiwari
Ans. Read Only Memory (ROM) is the memory that stores the data permanently. This means that it does not lose the data when the powers switched off. The data can be easily read from this type of memory but cannot be changed. ROM is commonly used in devices such as calculators, laser printers, etc.
ROM does not allow the random access of data rather it allows sequential access of data. It is less expensive as compared to RAM and other storage devices such as magnetic disk, etc.
ROM is divided into the following types-
Programmable Read Only Memory (PROM) can be programmed by the user for converting critical and lengthy operations into microprograms that are fused into a chip. They can be executed at a very high speed. Once operations are written into a PROM, they cannot be altered.
Erasable Programmable Read Only Memory (EPROM) can be erased and reprogrammed. Before to accept any new contents, it is removed from the processor and exposed to ultraviolet light for some time.
Electrically Erasable Programmable Read Only Memory (EEPROM) can be erased and reprogrammed with special electric pulses.
Flash ROM (FROM) is a type of EEPROM that stores the information using floating-gate transistors, which can store electric charge for a longer period of time as compared to the normal transistors. This memory is mainly used in the memory cards of mobile phones, digital cameras and ipods for storing data. The data stored in flash ROM memory can be easily transferred using transmission mediums like data cable, Bluetooth, and infrared technology. Flash ROM has faster speed of reading data as compared to other types of ROM. It uses continuous memory cells for storing data.