Good post by Scott D. Lowe (thank you)
Flash memory is a type of non-volatile memory storage, which can be electrically erased and programmed. What was the event that precipitated the introduction of this new storage medium? Well, it started in the mid-1980s, when Toshiba was working on a project to create a replacement for the EEPROM, a low-cost type of non-volatile memory, which could be erased and reprogrammed. The problem with the EEPROM was its cumbersome erasure process; it needed to be exposed to an ultraviolet light source to perform a complete erasure. To overcome this challenge, the E2PROM was created. The E2PROM type of memory cell was block erasable, but it was eight times the cost of the EEPROM. The high cost of the E2PROM led to rejection from consumers who wanted the low cost of EEPROM coupled with the block erasable qualities of the E2PROM.
Read on here