Flash eeprom memory systems and methods of using them

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 prolongs the useful life of the memory cells. Use of these various features provides a memory having a very high storage density and a long life, making it particularly useful as a solid state memory in place of magnetic disk storage devices in computer systems.