USB flash drives are often used for storage, data back-up and transfer of computer files. Compared with floppy disks or CDs, they are smaller, faster, have significantly more capacity, and are more durable due to a lack of moving parts. Additionally, they are immune to electromagnetic interference (unlike floppy disks), and are unharmed by surface scratches (unlike CDs). Until about 2005, most desktop and laptop computers were supplied with floppy disk drives in addition to USB ports, but floppy disk drives became obsolete after widespread adoption of USB ports and the larger USB drive capacity compared to the 1.44 MB 3.5-inch floppy disk.
Flash memory combines a number of older technologies, with lower cost, lower power consumption and small size made possible by advances in microprocessor technology. The memory storage was based on earlier EPROM and EEPROM technologies. These had limited capacity, were slow for both reading and writing, required complex high-voltage drive circuitry, and could be re-written only after erasing the entire contents of the chip.
Flash drives may present a significant security challenge for some organizations. Their small size and ease of use allows unsupervised visitors or employees to store and smuggle out confidential data with little chance of detection. Both corporate and public computers are vulnerable to attackers connecting a flash drive to a free USB port and using malicious software such as keyboard loggers or packet sniffers.
A recent development for the use of a USB Flash Drive as an application carrier is to carry the Computer Online Forensic Evidence Extractor (COFEE) application developed by Microsoft. COFEE is a set of applications designed to search for and extract digital evidence on computers confiscated from suspects.[48] Forensic software is required not to alter, in any way, the information stored on the computer being examined. Other forensic suites run from CD-ROM or DVD-ROM, but cannot store data on the media they are run from (although they can write to other attached devices, such as external drives or memory sticks).
In January 2013, tech company Kingston, released a flash drive with 1 TB of storage.[24] The first USB 3.1 type-C flash drives, with read/write speeds of around 530 MB/s, were announced in March 2015.[25] As of July 2016, flash drives within the 8 to 256 GB were sold more frequently than those between 512 GB and 1 TB units.[2][3] In 2017, Kingston Technology announced the release of a 2-TB flash drive.[26]
Like all flash memory devices, flash drives can sustain only a limited number of write and erase cycles before the drive fails.[71][unreliable source?][72] This should be a consideration when using a flash drive to run application software or an operating system. To address this, as well as space limitations, some developers have produced special versions of operating systems (such as Linux in Live USB)[73] or commonplace applications (such as Mozilla Firefox) designed to run from flash drives. These are typically optimized for size and configured to place temporary or intermediate files in the computer's main RAM rather than store them temporarily on the flash drive.
