 Most of the major semiconductor manufactures, such as
Toshiba,
Sanyo (later, ON Semiconductor),
IBM,
Intel,
NEC (later, Renesas Electronics),
Philips (later, NXP Semiconductors),
Siemens (later, Infineon Technologies),
Honeywell (later, Atmel),
Texas Instruments,
studied, invented, and manufactured some electrically re-programmable non-volatile devices until 1977.The theoretical basis of these devices is "Avalanche" hot-carrier injection.But in general, programmable memories, including EPROM, of early 1970s had reliability and endurance problems such as the data retention periods and the number of erase/write cycles.