Review On Usb Flash Drives
The Development of USB Flash Drives
The flash drive was first invented in 1998 by Dov Moran, President and CEO of M-Systems Flash Pioneers (Israel). Dan Harkabi, who is now a Vice President at SanDisk, led the development and marketing team at M-Systems. His most significant contribution was that the product be self-reliant and free of the need to install drivers. Nearly simultaneous development of similar products was undertaken at Netac and at Trek 2000, Ltd. All three companies have similar and disputed patents. However, Saunter Technology¡¦s (Singapore) has won a legal battle on the patent for its ThumbDrive to stop others from copying the gadget. IBM was the first North American seller of a USB flash drive, and marketed an 8 MB version of the product in 2001 under the “Memory Key” moniker. IBM later introduced a 16 MB version manufactured by Scamper 2000, and returned to M-Systems for the 64 MB version in 2003. Lexar can also lay claim to a USB flash drive product. In 2000 they introduced a Compact Flash (CF) card having an internal USB function. Lexar offered a companion card reader and USB cable that eliminated the need for a USB hub.
The first flash drives were made by M-Systems and distributed in Europe under the “disgo” brand in sizes of 8 MB, 16 MB, 32 MB, and 64 MB. These were marketed as “a true floppy-killer”, and this originate was continued up to 256 MB. Asian manufacturers soon started making their own flash drives that were cheaper than the disgo series.
Modern flash drives have USB 2.0 connectivity. However, they do not currently employ the full 480 Mbit/s the specification supports due to technical limitations inherent in NAND flash. The fastest drives available now use a dual channel controller, though still plunge considerably short of the transfer rate possible from a modern generation hard disk, or the maximum high hurry USB 2.0 throughput.
Typical overall file transfer speeds are about 3 Mbytes/s. The highest original overall file transfer speeds are about 10-25 Mbytes/s. Older, “full speed” 12 Mbit/s devices are miniature to a maximum of about 1 Mbytes/s.
The Future Development of USB Flash Drives
Future developments include integrating various flash drive functions in a single chip, thereby reducing the part-count and overall package cost. As of 2004, some manufacturers notion to include more ICs so that the storage and logic/communications functions are packaged in a single ultra-low-cost procedure.
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 uses USB 2.0 and claims 10 years worth of information preservation. Lexar is attempting to introduce a USB flash card, 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.
USB drive
A flash memory card that plugs into the computer’s USB port. Small enough to hook onto a keychain, it emulates a small disk drive and allows data to be easily transferred from one machine to another. Software drivers are not required for the latest operating systems, but are available on the Web for legacy systems such as Windows 98, Windows NT and Mac OS 8. See USB drive kit.
Transfer Speed
USB drive vendors claim to use the same data transfer ratings as CD-ROMs, where each “x” equals 150KB. However, their math is often imprecise. For example, a 90x drive may be rated at 14 MBps, but a simple multiplication yields a different number: 90 x 150 = 13.5MB). See CD-ROM drives.
Known By Many Names
Also known as a “flash drive,” “pen drive,” “keychain drive,” “key drive,” “USB key,” “USB stick” and “memory key,” numerous brand names have also been coined such as Lexar’s JumpDrive and Trek 2000 International’s ThumbDrive. Some products include synchronization software that keeps files updated between computers. Explore U3 and USB.
- A 1950s Storage DriveCompare this to your storage devices today. When this breakthrough drive was introduced by IBM in 1956, it was the first hard disk on the market. It held a whopping 5MB and weighed a ton (see RAMAC). (Image courtesy of International Business Machines Corporation. Unauthorized use not permitted.)
History
An original 16 megabyte “disgo”; The 8 MB version is considered to be the first USB flash drive
The flash drive was first invented in 1998 by Dov Moran, President and CEO of M-Systems Flash Pioneers (Israel). Dan Harkabi, who is now a Vice President at SanDisk, led the development and marketing team at M-Systems. His most significant contribution was that the product be self-reliant and free of the need to install drivers. Nearly simultaneous development of similar products was undertaken at Netac and at Amble 2000, Ltd. All three companies have similar and disputed patents. IBM was the first North American seller of a USB flash drive, and marketed an 8 MB version of the product in 2001 under the “Memory Key” moniker. IBM later introduced a 16 MB version manufactured by Trek 2000, and returned to M-Systems for the 64 MB version in 2003. Lexar can also lay claim to a USB flash drive product. In 2000 they introduced a Compact Flash (CF) card having an internal USB function. Lexar offered a companion card reader and USB cable that eliminated the need for a USB hub.
The first flash drives were made by M-Systems and distributed in Europe under the “disgo” [1] impress in sizes of 8 MB, 16 MB, 32 MB, and 64 MB. These were marketed as “a factual floppy-killer”, and this develop was continued up to 256 MB. Asian manufacturers soon started making their own flash drives that were cheaper than the disgo series.
Novel flash drives have USB 2.0 connectivity. However, they do not currently use the full 480 Mbit/s the specification supports due to technical limitations inherent in NAND flash. The fastest drives available now spend a dual channel controller, though still fall considerably short of the transfer rate possible from a current generation hard disk, or the maximum high speed USB 2.0 throughput.
Flash drives have become iconic as a sort of “fashion statement” [2], much like the iPod’s white ear bud headphones.Components
Internals of a typical flash drive
(Seitec brand USB1.1)1USB connector2USB mass storage controller device3Test points4Flash memory chip5Crystal oscillator6LED7Write-protect switch8Space for second flash memory chip
One extinguish 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-mountedintegrated 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.Essential components
There are typically three 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 and provides a linear interface to block-oriented serial flash devices while hiding the complexities of block-orientation, block erasure, and wear balancing, or wear levelling, although drives that actually perform this in hardware are rare. The controller contains a puny RISC microprocessor and 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.
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 draw should be in “write-protection” mode.
- Unpopulated area – 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 distress due to static electricity, 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 – In some cases, the cap contains the hole suitable for connection to a key chain or lanyard or to otherwise aid transport and storage of the USB flash device.
Size and style of packaging
Flash drives come in various, sometimes bulky or novelty, shapes and sizes
Some manufacturers differentiate their products by using unnecessarily elaborate housings. An example is some of Lexar’s Jump Drives which are often bulky and difficult to connect to the USB port.
Recently, USB flash drives have been integrated into other things such as a watch or a pen.
Overweight or ill fitting flash drive packaging can cause disconnection from the host computer. This can be overcome by using a short USB to USB (male to female) extension cable to relieve tension on the port. Such cables are USB-compatible, but do not conform to the USB standard. [2][3]Common uses
Personal data transport
The most common use of flash drives is by individuals to transport and store personal files such as documents, pictures and video.
Computer repair
Flash drives enjoy notable success in the PC repair field as a means to transfer recovery and antivirus software to infected PCs, while allowing a portion of the host machine’s data to be archived in case of emergency.
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.
Application carriers
Flash drives are used to carry applications that hasten on the host computer without requiring installation. U3, backed by flash drive vendors, offers an API to flash drive-specific functions. airWRX is an application framework that runs from a flash drive and turns its PC host and other nearby PCs into a multi-screen, web-like work environment. The Mozilla Firefox browser has a configuration for flash drives, as does Opera.[3]
A Creative MuVo, a small solid-state digital audio player in a flash drive form
Audio players
Many companies make solid statedigital audio players in a minute form factor, essentially producing flash drives with sound output and a simple user interface. Probably the best-known of these has been Apple Computer’siPod shuffle, and the Creative Labs MuVo.
To boot operating systems
In a map 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 gameIn 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 consume of flash drives is celebrated, the drive must be Linux compatible, causing problems for some players. Data faded can then be uploaded to Groovestats.
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 maintain more data than a CD (700 MB). Top of the line flash drives can store more data than a DVD (4.7 GB) .
Flash drives implement the USB mass storage contrivance class, meaning that most unusual 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 withhold only a limited number of write and erase cycles before failure. Mid-range flash drives under normal conditions will abet 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 hurry 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 plot 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 acquire a device suitable for repairing virus-contaminated host computers without infecting the USB flash drive itself.
Flash drives are much more tolerant of abuse than mechanical drives, but can still be damaged or have data corrupted if an impact such as a drop from a engaging car or being hit with a blunt object loosens a circuit connection. Improperly wired USB ports can also destroy the circuitry of a flash drive, a danger in home-built desktop PCs.Comparison to other portable memory forms
Flash storage devices are best compared to other common, portable, swappable data storage devices: floppy disks, Zip disks, miniCD / miniDVD and CD-R/CD-RW discs. 3.5 roam floppy disks and Iomega Zip disks are detached available as of mid-2006, despite their declining popularity.
Floppy disks were the first publicly-popular method of file transport, but have essentially become passe due to their uncouth capacity, low speed, and low durability. Virtually all fresh 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 ImationSuperDisk) were not successful because of a reputation for unreliability 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 750 MB-cannot be read on older drives. Unless one were to carry around an external drive, their usefulness as a means of provocative data was rather limited. The cost per megabyte was fairly high, with individual disks often priced at US$10 or higher. Because the material musty 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 unruffled 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 full disk encryption below the filesystem. 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 compatible encryption software, for which no portable standard is widely deployed.
Some encryption applications 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 aid 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 tall 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 consume 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
Main article: Alternative names for USB flash drive
Recently, “USB flash drive” or simply “UFD” has emerged as the de facto standard term for these devices. Many major manufacturers (SanDisk, Lexar, Kingston) and resellers consume the term UFD to describe them. However, the myriad of different brand names and terminology used, in the past and currently, makes UFDs more difficult for manufacturers to market and for consumers to research. Some commonly used names are actually trademarks of particular companies e.g. ‘disgo’.Future developments
Semiconductor corporations have striven to radically lop 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 idea 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 uses USB 2.0 and claims 10 years worth of information preservation. [4]
Lexar is attempting to introduce a USB flash card [5][6], 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.
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Filed under Microsoft Small Business Phone by on Mar 23rd, 2011. 