If you have used a personal comuter or a mobile computer, you know the words "RAM" and "ROM". RAM is an abbriviation of "Random Access Memory". The data in RAM disappears if you cut off the power, but RAM has big capacity and works rapidly. On the other hand, ROM is an abbrivation of "Read Only Memory". You can write to ROM only once like CD-R, but the data in ROM remains even if you cut off the power.
@Mobile machines need the memory that the data remains even if the power goes down and that can be erased and programmed many times. "EEPROM" meets that needs. EEPROM is abbreviation of "Electrically Erasable Programmable Read Only Memory" and it's electrically erasable and programmable as the name means. It is generally called "Flash Memory" because it's erased and programmed all at once by the block. Flash Memory is used in mobilephone and many mobile machineries. Moreover, memory cards to carry data in are also composed of EEPROM.
If you want to know more, I recommend that you look at the cites of electronics manufacturer.