Electronically erasable programmable read-only memory: like EPROM memory, EEPROM memory retains its contents when no power is available and can be both read from and written to. Unlike EPROM, information stored in EEPROM memory may be rewritten as and when required. In chip card terms the memory cannot become full and the lifespan of the card is determined by other factors. It is also sometimes known as E2PROM or simply E2.Chip cards can have EPROM or EEPROM memory.