Definition

• EEPROM, or electronically erasable programmable ROM, is a type of permanent memory storage system in a computer. ROM is read-only memory contained on a microchip that permanently stores digital data. EEPROM can be erased via an electric field and rewritten, and holds its contents without a constant power source.
  
  

Function

• EEPROM is used to store small amounts of digital data, such as on circuit boards, that must be saved if power is removed. EEPROM can also be used in products like real-time clocks, to store data such as calibration information that must remain available in the event of a power loss.
  
  

Disadvantages

• Unlike other read-only memory formats, EEPROM chips must be erased in entirety, not selectively, in order to be rewritten. EEPROM chips also can only be reprogrammed a certain amount of times, typically no more than hundreds of thousands.