1971: Erasable Programmable Read Only Memory (EPROM)
The first EPROM (sometimes also referred to as EROM) was invented by Dov Frohman of Intel in 1971 (patent #3,660,819). The first produced device was the i1701 with an 8x256-bit structure and a total capacity of 2,048 bits. An EPROM is a non-volatile memory device, i.e. a memory that retains its content even when the connected power is switched off. The technology uses arrays of floating-gate transistors that can be individually programmed. Data is erased via exposure to an ultraviolet light source. In 1978, George Perlegos at Intel developed the Intel 2816, the first EEPROM (Electrically Erasable Programmable Read Only Memory), which used the foundation of EPROMs, but leveraged a thin gate oxide layer to enable deletion without the need of an ultraviolet light source.