citation needed ] Flash memory now costs far less than byte-programmable EEPROM and has become the dominant memory type wherever a significant amount of non-volatile, solid state storage is needed. Contents 1 History 2 Principles of operation 2.1 Floating-gate transistor 2.2 NOR flash 2.2.1 Programming 2.2.2 Erasing 2.2.3 Internal charge pumps 2.3