USB

A USB flash drive consists of flash memory data storage device integrated with a USB (Universal Serial Bus) 1.1 or 2.0 interface. USB flash drives are typically removable and rewritable, much smaller than a floppy disk, and most weigh less than 30 g (1 oz).[1] Storage capacities in 2009 can be as large as 256 GB[2] with steady improvements in size and price per capacity. Some allow 1 million write or erase cycles[3][4] and have a 10-year data retention cycle.

Flash memory combines a number of older technologies, with lower cost, lower power consumption and small size made possible by recent advances in microprocessor technology. The memory storage was based on earlier EPROM and EEPROM technologies. These had very limited capacity, were very slow for both reading and writing, required complex high-voltage drive circuitry, and could only be re-written after erasing the entire contents of the chip.
^[update]