Flash memory

Flash memory is non-volatile memory|non-volatile, which means that it does not need power to maintain the information stored in the chip. In addition, flash memory offers fast read access times (although not as fast as volatile dynamic random access memory|DRAM memory used for main memory in PCs) and better kinetic shock resistance than hard disks. These characteristics explain the popularity of flash memory for applications such as storage on battery-powered devices. Another feature of flash memory is that when packaged in a "memory card", it is enormously durable, being able to withstand intense pressure, extremes of temperature and immersion in water.

Although technically a type of EEPROM, the term "EEPROM" is generally used to refer specifically to non-flash EEPROM which is eraseable in small blocks, typically bytes. Because an erase cycle is slow, the large size of a flash ROM's erase block can make programming it faster than old-style EEPROM.

Flash memory, regardless of format, supports only a limited number of erase/write cycles before a particular "sector" can no longer be written. Memory specifications generally allow 10,000 to 1,000,000 write cycles.