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.
Optical storage devices are among the cheapest methods of mass data storage after the hard drive. They are slower than their flash-based counterparts. Standard 120 mm optical discs are larger than flash drives and more subject to damage. Smaller optical media do exist, such as business card CD-Rs which have the same dimensions as a credit card, and the slightly less convenient but higher capacity 80 mm recordable MiniCD and Mini DVD. The small discs are more expensive than the standard size, and do not work in all drives.
The memory in flash drives is commonly engineered with multi-level cell (MLC) based memory that is good for around 3,000-5,000 program-erase cycles,[40] but some flash drives have single-level cell (SLC) based memory that is good for around 100,000 writes. There is virtually no limit to the number of reads from such flash memory, so a well-worn USB drive may be write-protected to help ensure the life of individual cells.
These products use flash memory chips, a stable, high-density storage medium, to hold your data. They pack a huge amount of information into a compact form factor. Most thumb drives are less than 2 inches long and easily fit in a pocket, laptop bag or purse. Models with built-in covers protect physical connectors from damage, and select products feature rugged silicon and metal shells that enhance heat and water resistance.

Some organizations forbid the use of flash drives, and some computers are configured to disable the mounting of USB mass storage devices by users other than administrators; others use third-party software to control USB usage. The use of software allows the administrator to not only provide a USB lock but also control the use of CD-RW, SD cards and other memory devices. This enables companies with policies forbidding the use of USB flash drives in the workplace to enforce these policies. In a lower-tech security solution, some organizations disconnect USB ports inside the computer or fill the USB sockets with epoxy.


Buying your flash drives in bulk may be a way to save in the long run depending on how many individual drives you need. Some brands or distributors may offer you discounts in an effort to move some of their inventories. eBay allows you to sort items by price or input your own custom price range. Using this feature may help you find the deal that works for you. Some standard price ranges you might find by default are the following:
Most USB flash drives weigh less than 30 g (1 oz).[31] While some manufacturers are competing for the smallest size[32] with the biggest memory,[33] some manufacturers differentiate their products by using elaborate housings, which are often bulky and make the drive difficult to connect to the USB port. Because the USB port connectors on a computer housing are often closely spaced, plugging a flash drive into a USB port may block an adjacent port. Such devices may carry the USB logo only if sold with a separate extension cable. Such cables are USB-compatible but do not conform to the USB standard.[34][35]
Flash drives implement the USB mass storage device class so that most modern operating systems can read and write to them without installing device drivers. The flash drives present a simple block-structured logical unit to the host operating system, hiding the individual complex implementation details of the various underlying flash memory devices. The operating system can use any file system or block addressing scheme. Some computers can boot up from flash drives.
The New York-based Human Rights Foundation collaborated with Forum 280 and USB Memory Direct to launch the "Flash Drives for Freedom" program.[80][81] The program was created in 2016 to smuggle flash drives with American and South Korean movies and television shows, as well as a copy of the Korean Wikipedia, into North Korea to spread pro-Western sentiment.[82][83]
USB 2.0 flash drives have a transfer rate of up to 480Mbps, while USB 3.0 flash drives allow for transfer rates 10 times faster — up to 4.8Gbps. However, you can only take advantage of this higher speed if your device has a USB 3.0 port. Although USB 3.0 flash drives and other devices are backwards compatible with USB 2.0 ports, they will only operate at a USB 2.0 rate.
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