The USB connector may be protected by a removable cap or by retracting into the body of the drive, although it is not likely to be damaged if unprotected. Most flash drives use a standard type-A USB connection allowing connection with a port on a personal computer, but drives for other interfaces also exist.
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.
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The patent application was filed by M-Systems in April Pua Khein-Seng from Malaysia has been credited with this invention. Flash drives are often measured by the rate at which they transfer data. Third generation USB flash drives were announced in late and became available in As of , the majority of laptop models still contained the 2. In January , tech company Kingston, released a flash drive with 1TB of storage. Internals of a typical USB flash drive. Inside the plastic casing is a small printed circuit board, which has some power circuitry and a small number of surface-mounted integrated circuits ICs.
Drives typically use the USB mass storage device class to communicate with the host. Flash memory combines a number of older technologies, with lower cost, lower power consumption and small size made possible by advances in microprocessor technology. 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.
Hardware designers later developed EEPROMs with the erasure region broken up into smaller "fields" that could be erased individually without affecting the others. Altering the contents of a particular memory location involved copying the entire field into an off-chip buffer memory, erasing the field, modifying the data as required in the buffer, and re-writing it into the same field. Flash drives are more or less a miniaturized version of this.
The development of high-speed serial data interfaces such as USB made semiconductor memory systems with serially accessed storage viable, and the simultaneous development of small, high-speed, low-power microprocessor systems allowed this to be incorporated into extremely compact systems. Serial access requires far fewer electrical connections for the memory chips than does parallel access , which has simplified the manufacture of multi- gigabyte drives.
Computers access modern [update] flash memory systems very much like hard disk drives, where the controller system has full control over where information is actually stored. The actual EEPROM writing and erasure processes are, however, still very similar to the earlier systems described above.
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. Most of these players can also be used as a conventional flash drive, for storing files of any type. 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.
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. USB flash drives with images of dragons, cats or aliens are very popular in Asia.
How to choose your USB memory sticks?
Also, standard FAT maintenance utilities e. 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. The memory in flash drives is commonly engineered with multi-level cell MLC based memory that is good for around 3,, program-erase cycles,  but some flash drives have single-level cell SLC based memory that is good for around , 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. As a result, a USB flash drive can last from a few days to several hundred years. Regardless of the endurance of the memory itself, the USB connector hardware is specified to withstand only around 1, insert-removal cycles. Counterfeit USB flash drives are sometimes sold with claims of having higher capacities than they actually have.
When plugged into a computer, they report themselves as being the larger capacity they were sold as, but when data is written to them, either the write fails, the drive freezes up, or it overwrites existing data. Software tools exist to check and detect fake USB drives,   and in some cases it is possible to repair these devices to remove the false capacity information and use its real storage limit. Transfer speeds are technically determined by the slowest of three factors: the USB version used, the speed in which the USB controller device can read and write data onto the flash memory, and the speed of the hardware bus , especially in the case of add-on USB ports.
These speeds are for optimal conditions; real-world speeds are usually slower. In particular, circumstances that often lead to speeds much lower than advertised are transfer particularly writing of many small files rather than a few very large ones, and mixed reading and writing to the same device. The examples given are chosen to illustrate extremes The most common use of flash drives is to transport and store personal files, such as documents, pictures and videos. Individuals also store medical information on flash drives for emergencies and disaster preparation.
With wide deployment s of flash drives being used in various environments secured or otherwise , the issue of data and information security remains important. The use of biometrics and encryption is becoming the norm with the need for increased security for data; on-the-fly encryption systems are particularly useful in this regard, as they can transparently encrypt large amounts of data.
USB flash drives
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. COFEE is a set of applications designed to search for and extract digital evidence on computers confiscated from suspects. Usually, new firmware image is downloaded and placed onto a FAT16 - or FAT32 -formatted USB flash drive connected to a system which is to be updated, and path to the new firmware image is selected within the update component of system's firmware. Also, HP has introduced a USB floppy drive key , which is an ordinary USB flash drive with additional possilibility for performing floppy drive emulation, allowing its usage for updating system firmware where direct usage of USB flash drives is not supported.
Desired mode of operation either regular USB mass storage device or of floppy drive emulation is made selectable by a sliding switch on the device's housing. 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. Original flash memory designs had very limited estimated lifetimes. The failure mechanism for flash memory cells is analogous to a metal fatigue mode; the device fails by refusing to write new data to specific cells that have been subject to many read-write cycles over the device's lifetime.
Originally, this potential failure mode limited the use of "live USB" system to special-purpose applications or temporary tasks, such as:. As of [update] , newer flash memory designs have much higher estimated lifetimes.
Several manufacturers are now offering warranties of 5 years or more. Such warranties should make the device more attractive for more applications. By reducing the probability of the device's premature failure, flash memory devices can now be considered for use where a magnetic disk would normally have been required.
Flash drives have also experienced an exponential growth in their storage capacity over time following the Moore's Law growth curve. Storage capacities in this range have traditionally been considered to offer adequate space, because they allow enough space for both the operating system software and some free space for the user's data. In particular, Mac OS X However, for installation of Windows 7 and later versions, using USB flash drive with hard disk drive emulation as detected in PC's firmware is recommended in order to boot from it.
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Transcend is the only manufacturer of USB flash drives containing such feature. 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. 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 independent software vendors 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 and portable application creators , such as VMware ThinApp for Windows or RUNZ for Linux can be used to run software from a flash drive without installation. In October , Apple Inc. 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. Some value-added resellers are now using a flash drive as part of small-business turnkey solutions e.
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. Flash drives also have disadvantages.
They are easy to lose and facilitate unauthorized backups. A lesser setback for flash drives is that they have only one tenth the capacity of hard drives manufactured around their time of distribution. Many companies make small solid-state digital audio players , essentially producing flash drives with sound output and a simple user interface. Some of these players are true USB flash drives as well as music players; others do not support general-purpose data storage.
Other applications requiring storage, such as digital voice or sound recording , can also be combined with flash drive functionality. Many of the smallest players are powered by a permanently fitted rechargeable battery, charged from the USB interface. Fancier devices that function as a digital audio player have a USB host port type A female typically.
Digital 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. This allows a USB flash drive containing media files in a variety of formats to be played directly on devices which support the format. In addition to five high- bitrate MP3s , it also included a video, pictures, lyrics, and guitar tablature. Rave , a compilation album released by the Kiss Network in April Ideal for storing, copying and moving data, games, image material and music files.
These ultra-portable drives are tiny and lightweight enough to carry anywhere, and are all designed to slip neatly onto your keyring. Choose from USB 2.
Data encryption and password protection software options allow you to establish a password-protected folder on your drive for private use, protecting your files with secure AES encryption. For the ultimate portable storage solution, take your files anywhere, securely, with a USB flash drive. Back to top. Title Mr. First name.