A memory system made up of electrically programmable read only memory (EPROM) or flash electrically erasable and programmable read only memory (EEPROM) cells. An intelligent programming technique allows each memory cell to store more than the usual one bit of information. An intelligent erase algorithm...http://www.google.de/patents/US5043940?utm_source=gb-gplus-sharePatent US5043940 - Flash EEPROM memory systems having multistate storage cells
