Nonvolatile storage that can be electrically erased and reprogrammed so that software images can be stored, booted, and rewritten as necessary. Flash memory was developed by Intel and is licensed to other semiconductor companies
Flash memory is a special kind of memory chip that can be erased and programmed, and retains information after the system has shut down. Flash memory in digital cameras allows them to retain images even after the batteries die.
Flash memory is called so because the entire sections of the microchip are erased at once or (flashed). Flash memory cards lose power when they are disconnected (removed) from the PC, yet the data stored in it is retained for indefinitely long time or until it is rewritten. The are two basic type of Flash cards: PC Cards (linear cards) and ATA Flash PC cards. For details go here.