A flash drive is a data storage device that includes flash memory with an integrated USB interface. A typical USB drive is removable, rewritable, and smaller than an optical disc, and usually weighs less than 30 g (1 oz). Since first offered for sale in late 2000, the storage capacities of USB drives range from 8 to 256 gigabytes (GB), 512 GB and 1 terabyte (TB). As of 2023, 2 TB flash drives were the largest currently in production. Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and are thought to physically last between 10 and 100 years under normal circumstances.
A SanDisk Cruzer USB drive from 2011, with 4 GB of storage capacity
A SanDisk Ultra Flair USB drive from 2020, attached to an HP laptop
Transcend JetFlash from 2014
SanDisk 1 TB USB-C flash drive (2020 model) next to a 50 cent euro coin
Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both use the same cell design, consisting of floating gate MOSFETs. They differ at the circuit level depending on whether the state of the bit line or word lines is pulled high or low: in NAND flash, the relationship between the bit line and the word lines resembles a NAND gate; in NOR flash, it resembles a NOR gate.
A disassembled USB flash drive in 2005. The chip on the left is flash memory. The controller is on the right.
NOR flash by Intel
Serial Flash: Silicon Storage Tech SST25VF080B
An Intel mSATA SSD in 2020