Audio players
- Many companies make solid state digital audio players in a small form factor, essentially producing flash drives with sound output and a simple user interface. Probably the best-known of these has been Apple Computer's iPod shuffle, and the Creative Labs MuVo.
To boot operating systems
- In a way similar to that used in LiveCD, one can launch any operating system from a bootable flash drive, known as a LiveUSB.
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. While use of flash drives is common, the drive must be Linux compatible, causing problems for some players. Data used can then be uploaded to Groovestats. [2]
Strengths and weaknesses
Flash drives are nearly impervious to the scratches and dust that were problematic for previous forms of portable storage, such as compact discs and floppy disks, and their durable solid-state design means they often survive casual abuse. This makes them ideal for transporting personal data or work files from one location to another, such as from home to school or office or for carrying around personal data that the user typically wants to access in a variety of places. The near-ubiquity of USB support on modern computers means that such a drive will work in most places.
Flash drives are also a relatively dense form of storage, where even the cheapest will store dozens of floppy disks worth of data. Some can hold more data than a CD. Top of the line flash drives can even hold more data than a DVD.
Flash drives implement the USB mass storage device class, meaning that most modern operating systems can read and write to flash drives without any additional device drivers. Instead of exposing the complex technical detail of the underlying flash memory devices, the flash drives export a simple block-structured logical unit to the host operating system. The operating system can use whatever type of filesystem or block addressing scheme it wants. Some computers have the ability to boot up from flash drives.
Like all flash memory devices, flash drives can sustain only a limited number of write and erase cycles before failure. Mid-range flash drives under normal conditions will support several hundred thousand cycles, although write operations will gradually slow as the device ages. 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) 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 memory rather than store them temporarily on the flash drive.
Most USB flash drives do not employ a write-protect mechanism. Such a switch on the housing of the drive itself would keep the host computer from writing or modifying data on the drive. Write-protection would make a device suitable for repairing virus-contaminated host computers without infecting the USB flash drive itself.
Flash drives are more tolerant of abuse than mechanical drives, but can still be damaged or have data corrupted if an impact loosens circuit connections.
Comparison to other portable memory forms
Flash storage devices are best compared to other common, portable, swappable data storage devices: floppy disks, Zip disks, and CD-R/CD-RW discs. 3.5 inch floppy disks and Iomega Zip disks are still available as of mid-2006, despite their declining popularity. While for many purposes it would be ideal to transport files between computers wirelessly, not all computers are equipped with wireless cards, and networks are not readily available.
Floppy disks were the first publicly-popular method of file transport, but have essentially become obsolete due to their low capacity, low speed, and low durability. Virtually all new computers include USB ports, and many of them are now sold without a floppy drive, the Apple iMac being the first to ship this way. Floppy disks are still in use because of their low cost and ease of use with older systems. Attempts to extend the floppy standard (such as the Imation SuperDisk) were not successful because of a reputation for unreliablity and the lack of a single standard for PC vendors to adopt.
The Iomega Zip drive enjoyed some popularity, but never reached the point of ubiquity in computers. Also, the larger sizes of Zip-now up to 750MB-cannot be read on older drives. Unless one were to carry around an external drive, their usefulness as a means of moving data was rather limited. The cost per megabyte was fairly high, with individual disks often priced at $10 USD or higher. Because the material used for creating the storage medium in Zip disks is similar to that used in floppy disks, Zip disks have a higher risk of failure and data loss. Larger removable storage media, like Iomega's Jaz drive, had even higher costs, both in drives and in media, and as such were never feasible as a floppy alternative.
CD-R and CD-RW are swappable storage media alternatives. Unlike Zip and floppy drives, DVD and CD recorders are increasingly common in personal computer systems. CD-Rs can only be written to once, and the more expensive CD-RWs are only rated up to 1,000 erase/write cycles, whereas modern NAND-based flash drives often last for 500,000 or more erase/write cycles. Optical storage devices are also usually slower than their flash-based counterparts. Compact discs with an 11.5 cm diameter can also be inconveniently large and, unlike flash drives, cannot fit into a pocket or hang from a keychain. Smaller CDs are available, and these are an exception. There is also no standard file system for rewriteable optical media; packet-writing utilities like DirectCD and InCD exist, but produce discs that are not universally readable, despite claiming to be based on the UDF standard. The upcoming Mount Rainier standard addresses this shortcoming in CD-RW media, but is still not supported by most DVD and CD recorders or major operating systems.
Security
Some flash drives feature encryption of the data stored on them, generally using an encrypted filesystem rather than a conventional one. This prevents an unauthorized person from accessing the data stored on it. The disadvantage is that the drive is accessible only in the minority of computers which have the same encryption software, for which no portable standard is widely deployed. Unless the encryption software is stored unencrypted on the drive, the user must carry the large cryptographic key around by some other means.
Some encryption applications (such as TrueCrypt, CryptoBuddy and Private Disk) allow running without installation. The executable files can be stored on the USB drive, together with the encrypted file image. The encrypted partition can be accessed on any computer running Microsoft Windows. Other flash drives allow the user to configure secure and public partitions of different sizes. Executable files for Windows, Macintosh, and Linux are usually included on the drive.
Newer flash drives support biometric fingerprinting to confirm the user's identity. As of mid-2005, this was a relatively costly alternative to standard password protection offered on many new USB flash storage devices.
Some manufacturers deploy physical authentication tokens in the form of a flash drive. 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. The system is designed so the target machine will not operate except when the flash drive device is plugged into it. Some of these "PC lock" devices also function as normal flash drives when plugged into other machines.
Flash drives present a significant security challenge for large organizations. Their small size and ease of use allows unsupervised visitors or unscrupulous employees to smuggle confidential data out with little chance of detection. Equally, corporate and public computers alike are vulnerable to attackers connecting a flash drive to a free USB port and using malicious software such as rootkits or packet sniffers. To prevent this, some organizations forbid the use of flash drives, and some computers are configured to disable the mounting of USB mass storage devices by ordinary users, a feature introduced in Windows XP service pack 2; others use third-party software to control USB usage. In a lower-tech security solution, some organizations disconnect USB ports inside the computer or fill the USB sockets with epoxy.
Naming
-
No commonly recognized term for USB Flash drives has emerged. The resulting confusion makes them more difficult for manufacturers to market and for consumers to research.
Future developments
Semiconductors corporations have striven to radically reduce the cost of the components in a flash drive by integrating various flash drive functions in a single chip, thereby reducing the part-count and overall package cost. As of 2004, some manufacturers plan to include more ICs so that the storage and logic/communications functions are packaged in a single ultra-low-cost device.
In efforts to focus on increasing capacities, 64 MB and smaller capacity flash memory has been largely discontinued, and 128 MB capacity flash memory is being phased out. Kanguru has recently released a 64 GB flash memory drive that utilizes USB 2.0 and claims 10 years worth of information preservation. [3]
Lexar is attempting to introduce a USB Flash Card [4] [5], which would be a compact USB flash drive intended to replace various kinds of flash memory cards.
SanDisk has introduced a new technology to allow controlled storage and usage of copyrighted materials on flash drives, primarily for use by students. This technology is termed FlashCP.
Trivia
- In 2004, the German punk band WIZO was the first musical group to release music in MP3 format on a USB drive, titled the WIZO Stick-EP. [4]
- In the films The Recruit & Collateral, thumb drives play an important role in the plot.
- Some flash drives can retain their memory after being submerged in water [5], even through a machine wash. Leaving the flash drive out to dry completely has been known to result in a working drive with no future problems.
- Isolinear chips, fictional devices similar to USB drives in design and function, featured regularly in Star Trek: The Next Generation over 10 years before their real world counterparts were invented.
See also
Notes
External links
Security
HOWTO pages