Backup

Some value-added resellers are now using a flash drive as part of small-business turnkey solutions (e.g. point-of-sale systems). The drive is used as a backup medium: at the close of business each night, the drive is inserted, and a database backup is saved to the drive. Alternatively, the drive can be left inserted through the business day, and data regularly updated. In either case, the drive is removed at night and taken offsite.

This is simple for the end-user, and more likely to be done;
The drive is small and convenient, and more likely to be carried off-site for safety;
The drives are less fragile mechanically and magnetically than tapes;
The capacity is often large enough for several backup images of critical data;
And flash drives are cheaper than many other backup systems.

It is also easy to lose these small devices, and easy for people without a right to data to take illicit backups.

Brand and product promotion

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). They may be given away for free, sold at less than wholesale price, or included as a bonus with another purchased product.

Usually, such drives will be custom-stamped with a company's logo, as a form of advertising to increase mind share and brand awareness. The drive may be blank drive, or preloaded with graphics, documentation, web links, Flash animation or other multimedia, and free or demonstration software. Some preloaded drives are read-only; others are configured with a read-only and a writeable partition. Dual-partition drives are more expensive.

Flash drives can be set up to automatically launch stored presentations, websites, articles, and any other software immediately on insertion of the drive using the Microsoft Windows AutoRun feature[19]. Autorunning software this way does not work on all computers, and is normally disabled by security-conscious users.

In arcades

In the arcade game In the Groove and more commonly In The Groove 2, flash drives are used to transfer high scores, screenshots, dance edits, and combos throughout sessions. As of software revision 21 (R21), players can also store custom songs and play them on any machine on which this feature is enabled. While use of flash drives is common, the drive must be Linux compatible.

In the arcade games Pump it Up NX2 and Pump it Up NX Absolute, a special produced flash drive is used as a "save file" for unlocked songs, as well as progressing in the WorldMax and Brain Shower sections of the game.

In the arcade game Dance Dance Revolution X, an exclusive USB flash drive was made by Konami for the purpose of the link feature from its Sony PlayStation 2 counterpart.

Music storage and marketing

Data audio files can be transported from one computer to another like any other file, and played on a compatible media player (with caveats for DRM-locked files). In addition, many home Hi-Fi and car stereo head units are now equipped with a USB port. This allows a USB flash drive containing media files in a variety of formats to be played directly on devices which support the format.

Artists have sold or given away USB flash drives, with the first instance believed to be in 2004 when the German band WIZO released the "Stick EP", only as a USB drive. In addition to five high-bitrate MP3s, it also included a video, pictures, lyrics, and guitar tablature. Subsequently artists including Kanye West[17] , Nine Inch Nails and Ayumi Hamasaki [18] have released music and promotional material on USB flash drives.

Audio players

Many companies make small solid-state digital audio players, essentially producing flash drives with sound output and a simple user interface. Examples include the Creative MuVo, Philips GoGear and the iPod shuffle. Some of these players are true USB flash drives as well as music players; others do not support general-purpose data storage.

Many of the smallest players are powered by a permanently fitted rechargeable battery, charged from the USB interface.

Windows Vista and Windows 7 ReadyBoost

In Windows Vista and the upcoming Windows 7, the ReadyBoost feature allows use of some flash drives to augment operating system memory.

Booting operating systems

Most current PC firmware permits booting from a USB drive, allowing the launch of an operating system from a bootable flash drive. Such a configuration is known as a Live USB.

While a Live USB could be used for general-purpose applications, size and memory wear make them poor choices compared to alternatives. They are more suited to special-purpose or temporary tasks, such as:

Loading a minimal, hardened kernel for embedded applications (e.g. network router, firewall).
Bootstrapping an operating system install or disk cloning operation, often across a network.
Maintenance tasks, such as virus scanning or low-level data repair, without the primary host operating system loaded.

Computer forensics and law enforcement

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[15]. Forensic software should not alter the information stored on the computer being examined in any way; 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).

Application carriers

Flash drives are used to carry applications that run on the host computer without requiring installation. While any standalone application can in principle be used this way, many programs store data, configuration information, etc. on the hard drive and registry of the host computer

The U3 company works with drive makers (parent company SanDisk as well as others) to deliver custom versions of applications designed for Microsoft Windows from a special flash drive; U3-compatible devices are designed to autoload a menu when plugged into a computer running Windows. Applications must be modified for the U3 platform not to leave any data on the host machine. U3 also provides a software framework for ISVs interested in their platform.

Ceedo is an alternative product with the key difference that it does not require Windows applications to be modified in order for them to be carried and run on the drive.

Similarly, other application virtualization solutions, such as VMware ThinApp (for Windows) or RUNZ (for Linux) can be used to run software from a flash drive without installation.

A wide range of portable applications which are all free of charge, and able to run off a computer running Windows without storing anything on the host computer's drives or registry, can be found in the list of portable software.

Uses of Flash Drive

Personal data transport

The most common use of flash drives is to transport and store personal files such as documents, pictures and videos. Individuals also store medical alert information on MedicTag flash drives for use in emergencies and for disaster preparation.

Secure storage of data, application and software files

With wide deployment(s) of flash drives being used in various environments (secured or otherwise), the issue of data and information security remains of the utmost importance. The use of biometrics and encryption is becoming the norm with the need for increased security for data; OTFE systems such as FreeOTFE and TrueCrypt are particularly useful in this regard, as they can transparently encrypt large amounts of data. In some cases a Secure USB Drive may use a hardware-based encryption mechanism that uses a hardware module instead of software for strongly encrypting data.

System administration

Flash drives are particularly popular among system and network administrators, who load them with configuration information and software used for system maintenance, troubleshooting, and recovery. They are also used as a means to transfer recovery and antivirus software to infected PCs, allowing a portion of the host machine's data to be archived. As the drives have increased in storage space, they have also replaced the need to carry a number of CD ROMs and installers which were needed when reinstalling or updating a system.

File system

Most flash drives ship preformatted with the FAT or FAT 32 file system. The ubiquity of this file system allows the drive to be accessed on virtually any host device with USB support. Also, standard FAT maintenance utilities (e.g. ScanDisk) can be used to repair or retrieve corrupted data. However, because a flash drive appears as a USB-connected hard drive to the host system, the drive can be reformatted to any file system supported by the host operating system.

Defragmenting: Flash drives can be defragmented, but this brings little advantage as there is no mechanical head slowed down by having to move from fragment to fragment. Flash drives often have very large internal sector size, so defragmenting means accessing fewer sectors for example to erase a file. Defragmenting though shortens the life of the drive by making many unnecessary writes.

Even Distribution: Some file systems are designed to distribute usage over an entire memory device without concentrating usage on any part (e.g., for a directory); this even distribution prolongs the life of simple flash memory devices. Some USB flash drives have this functionality built into the software controller to prolong device life, while others do not, therefore the end user should check the specifications of his device prior to changing the file system for this reason.

Hard Drive: Sectors are 512 bytes long, for compatibility with hard drives, and first sector can contain a Master Boot Record and a partition table. Therefore USB flash units can be partitioned as hard drives.

Size and style of packaging

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 only carry the USB logo if sold with a separate extension cable.

USB flash drives have been integrated into other commonly-carried items such as watches, pens, and even the Swiss Army Knife; others have been fitted with novelty cases such as toy cars or LEGO bricks. The small size, robustness and cheapness of USB flash drives make them an increasingly popular peripheral for case modding.

Heavy or bulky flash drive packaging can make for unreliable operation when plugged directly into a USB port; this can be relieved by a USB extension cable. Such cables are USB-compatible, but do not conform to the USB standard

Additional components

The typical device may also include:

Jumpers and test pins – for testing during the flash drive's manufacturing or loading code into the microprocessor.

LEDs – indicate data transfers or data reads and writes.

Write-protect switches – indicate whether the device should be in "write-protection" mode.

Unpopulated space – provides space to include a second memory chip. Having this second space allows the manufacturer to develop only one printed circuit board that can be used for more than one storage size device, to meet the needs of the market.

USB connector cover or cap – reduces the risk of damage and prevents the ingress of fluff or other contaminants, and improves overall device appearance. Some flash drives do not feature a cap, but instead have retractable USB connectors. Other flash drives have a "swivel" cap that is permanently connected to the drive itself and eliminates the chance of losing the cap.

Transport aid – the cap or the main body often contains a hole suitable for connection to a key chain or lanyard.

Some drives offer expandable storage via an internal memory card slot, much like a memory card reader.

Essential components

There are typically four parts to a flash drive:

Male type-A USB connector – provides an interface to the host computer.

USB mass storage controller – implements the USB host controller. The controller contains a small microcontroller with a small amount of on-chip ROM and RAM.

NAND flash memory chip – stores data. NAND flash is typically also used in digital cameras.

Crystal oscillator – produces the device's main 12 MHz clock signal and controls the device's data output through a phase-locked loop.

Design and implementation

One end of the device is fitted with a single male type-A USB connector. Inside the plastic casing is a small printed circuit board. Mounted on this board is some simple power circuitry and a small number of surface-mounted integrated circuits (ICs). Typically, one of these ICs provides an interface to the USB port, another drives the onboard memory, and the other is the flash memory.

Drives typically use the USB mass storage device class to communicate with the host.

History

First Commercial Product

Trek Technology and IBM began selling the first USB flash drives commercially in 2000. Singaporean company Trek Technology sold a model dubbed the "ThumbDrive," and IBM marketed the first such drives in North America, with its product the "DiskOnKey" (which was manufactured by the Israeli company M-Systems). IBM's USB flash drive became available on December 15, 2000,^[6][7] and had a storage capacity of 8 MB, more than five times the capacity of the commonly used floppy disks (floppy disks having a capacity of 1.44MB).

In 2000 Lexar introduced a Compact Flash (CF) card with a USB connection, and a companion card read/writer and USB cable that eliminated the need for a USB hub.

On July 24, 2002 Netac Technology was granted a highly-contested Chinese patent for the USB flash drive.^[8]

In 2004 Trek Technology brought several lawsuits against other USB flash drive manufacturers and distributors in an attempt to assert its patent rights to the USB flash drive. A court in Singapore ordered competitors to cease selling similar products^[9] that would be covered by Trek's patent, but a court in the United Kingdom revoked^[10] one of Trek's patents in that country.

Second generation

Modern flash drives have USB 2.0 connectivity. However, they do not currently use the full 480 Mbit/s (60MB/s) the USB 2.0 Hi-Speed specification supports due to technical limitations inherent in NAND flash. The fastest drives currently available use a dual channel controller, although they still fall considerably short of the transfer rate possible from a current generation hard disk, or the maximum high speed USB throughput.

Typical overall file transfer speeds vary considerably, and should be checked before purchase. Speeds may be given in Mbyte per second, Mbit per second, or optical drive multipliers such as "180X" (180 times 150 KiB per second). Typical fast drives claim to read at up to 30 megabytes/s (MB/s) and write at about half that. Older "USB full speed" 12 Mbit/s devices are limited to a maximum of about 1 MB/s.

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Creating a USB Drive

A USB flash drive consists of a NAND-type flash memory data storage device integrated with a USB (Universal Serial Bus) interface. USB flash drives are typically removable and rewritable, much smaller than a floppy disk, and most weigh less than an ounce (30 g).^[1] Storage capacities can range from 64 MB to 256 GB^[2] with steady improvements in size and price per capacity. Some allow 1 million write or erase cycles^[3][4] and have 10-year data retention,^[5] connected by USB 1.1 or USB 2.0.

USB flash drives offer potential advantages over other portable storage devices, particularly the floppy disk. They have a more compact shape, operate faster, hold much more data, have a more durable design, and operate more reliably due to their lack of moving parts. Additionally, it has become increasingly common for computers to be sold without floppy disk drives. USB ports, on the other hand, appear on almost every current^[update] mainstream PC and laptop. These types of drives use the USB mass storage standard, supported natively by modern operating systems such as Windows, Mac OS X, Linux, and other Unix-like systems. USB drives with USB 2.0 support can also operate faster than an optical disc drive, while storing a larger amount of data in a much smaller space.

Nothing actually moves in a flash drive: the term drive persists because computers read and write flash-drive data using the same system commands as for a mechanical disk drive, with the storage appearing to the computer operating system and user interface as just another drive.^[4]

A flash drive consists of a small printed circuit board protected inside a plastic, metal, or rubberized case, robust enough for carrying with no additional protection—in a pocket or on a key chain, for example. The USB connector is protected by a removable cap or by retracting into the body of the drive, although it is not likely to be damaged if exposed (but it may damage other items, for example a bag it is placed in). Most flash drives use a standard type-A USB connection allowing plugging into a port on a personal computer, but drives for other interfaces also exist.

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