Electrically Erasable and Programmable Read-Only Memory (EEPROM) is a programmable ROM that allows the stored data to be erased electrically. EEPROM:EEPROM is the short form for Electrically Erasable Programmable Read Only Memory. It is similar to EPROM and thus developed to overcome the drawbacks of EPROMs. It is erased and programmed electrically i. e. it uses electrical signals instead of ultra violet rays. The erasing and programming of data takes 4 to 10 milliseconds. Any byte can be erased at a time instead of the entire chip. The chip can be erased and re programmed for around ten thousand times, though the process is flexible but slowAdditional Information PROM: PROM stands for Programmable Read Only Memory. PROM is manufactured as a blank memory. And as its name suggests Programmable, it is programmed after manufacturing. The user buys a blank memory and enters the desired contents using a PROM program. EPROM: EPROM can be erased by exposing it to ultra violet light for a particular length of time using an EPROM eraser. After exposing, the chip returns to its initial state and can be reprogrammed.