Flash memory is a type of constantly-powered nonvolatile memory that can be erased and reprogrammed in units of memory called blocks. It is a variation of EEPROM which, unlike flash memory, is erased and rewritten at the byte level, which is slower than flash memory updating. Flash memory is often used to hold control code such as the basic input / output system (BIOS) in a personal computer. When BIOS needs to be changed, the flash memory can be written to in block sizes, making it easy to update. On the other hand, flash memory is not useful as RAM because RAM needs to be addressable at the byte level.
Flash memory gets its name because the microchip is organized so that a section of memory cells are erased in a single action or "flash." The erasure is caused by Fowler-Nordheim tunneling in which electrons pierce through a thin dielectric material to remove an electronic charge from a floating gate associated with each memory cell.
Reprogramming together with high storage density, in parallel or serial access
Critical to successful designs in wireless, telecom and automotive
Real-time protection for stored data
More density in less space