USB flash drive

[6] 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 (shelf storage time[note 4]).

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.

Some devices combine the functionality of a portable media player with USB flash storage; they require a battery only when used to play music on the go.

On April 5, 1999, Amir Ban, Dov Moran, and Oron Ogdan of M-Systems, an Israeli company, filed a patent application entitled "Architecture for a Universal Serial Bus-Based PC Flash Disk".

[16][17][18] However, the question of who was the first to invent the USB flash drive has multiple claims persist, the Natec Technology get the basic copyright of American in December 7, 2004.

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.

Many low-cost MP3 players simply add extra software and a battery to a standard flash memory control microprocessor so it can also serve as a music playback decoder.

[35][36] USB flash drives have been integrated into other commonly carried items, such as watches, pens, laser pointers, and even the Swiss Army Knife; others have been fitted with novelty cases such as toy cars or Lego bricks.

[37] The small size, robustness and cheapness of USB flash drives make them an increasingly popular peripheral for case modding.

Some USB flash drives have this 'wear leveling' feature built into the software controller to prolong device life, while others do not, so it is not necessarily helpful to install one of these file systems.

[42] 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.

Software tools exist to check and detect fake USB drives,[45] [46][47] and in some cases it is possible to repair these devices to remove the false capacity information and use its real storage limit.

Originally, this potential failure mode limited the use of "live USB" system to special-purpose applications or temporary tasks, such as: As of 2011[update], newer flash memory designs have much higher estimated lifetimes.

Installers of some operating systems can be stored to a flash drive instead of a CD or DVD, including various Linux distributions, Windows 7 and newer versions, and macOS.

Many companies make small solid-state digital audio players, essentially producing flash drives with sound output and a simple user interface.

Some LCD monitors for consumer HDTV viewing have a dedicated USB port through which music and video files can also be played without use of a personal computer.

[61] Subsequently, artists including Nine Inch Nails and Kylie Minogue[62] have released music and promotional material on USB flash drives.

[63] The availability of inexpensive flash drives has enabled them to be used for promotional and marketing purposes, particularly within technical and computer-industry circles (e.g., technology trade shows).

The drive may be blank, or preloaded with graphics, documentation, web links, Flash animation or other multimedia, and free or demonstration software.

Specially manufactured flash drives are available that have a tough rubber or metal casing designed to be waterproof and virtually "unbreakable".

Channel Five's Gadget Show cooked one of these flash drives with propane, froze it with dry ice, submerged it in various acidic liquids, ran over it with a jeep and fired it against a wall with a mortar.

Devices with removable storage like older Yamaha music keyboards are also dependent on floppy disks, which require computers to process them.

Packet-writing utilities such as DirectCD and InCD are available but produce discs that are not universally readable (although based on the UDF standard).

Unlike solid-state memory, hard drives are susceptible to damage by shock (e.g., a short fall) and vibration, have limitations on use at high altitude, and although shielded by their casings, are vulnerable when exposed to strong magnetic fields.

There are products in today's market that will emulate these legacy drives for both tape and disk (SCSI1/SCSI2, SASI, Magneto optic, Ricoh ZIP, Jaz, IBM3590/ Fujitsu 3490E and Bernoulli for example) in state-of-the-art Compact Flash storage devices – CF2SCSI.

These are used to control access to a sensitive system by containing encryption keys or, more commonly, communicating with security software on the target machine.

To address this, as well as space limitations, some developers have produced special versions of operating systems (such as Linux in Live USB)[76] 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.

For example, write protection makes a device suitable for repairing virus-contaminated host computers without the risk of infecting a USB flash drive itself.

[81] SanDisk introduced a digital rights management technology called FlashCP that they had purchased in 2005 to control the storage and usage of copyrighted materials on flash drives, primarily for use by students.