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.
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.
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. 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.
Application carriers
Flash drives are used to carry applications that run on the host computer without requiring installation. While any standalone application can be used this way, the U3 company, works with drive makers (parent company SanDisk as well as others) to deliver Windows applications from a flash drive custom-tuned for this purpose. 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.
Friday, July 25, 2008
Technology
Flash memory is actually a combination of a number of older technologies, with the low cost, low power consumption and small size being made possible by recent advances in microprocessor technology. The memory storage is based on earlier EPROM and EEPROM technologies. These had very limited capacity, were very slow for both reading and writing, required complex high-voltage drive circuitry, and could only be re-written after erasing the entire contents of the chip.
Later EEPROMS were developed where the erasure region was broken up into smaller "fields" that could be erased individually without affecting the others. Altering the contents of a particular memory location involved first copying the entire field into an off-chip buffer memory, erasing the field, and then re-writing the data back into the same field, making the necessary alteration to the relevant memory location while doing so. This required considerable computer support, and PC-Based EEPROM flash memory systems often carried their own dedicated microprocessor system. Flash drives are more or less a miniaturized version of this.
The development of high-speed serial data interfaces such as USB for the first time made serially accessed storage memory systems viable, and the simultaneous development of small, high-speed, low-power microprocessor systems allowed this to be incorporated into extremely compact systems. Serial access also greatly reduced the number of electrical connections required for the memory chips, which has allowed the successful manufacture of multi-gigabyte capacities. (Every external electrical connection is a potential source of manufacturing failure, and with traditional manufacturing, a point is rapidly reached where the successful yield approaches zero).
Modern flash memory systems are accessed 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 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.
Later EEPROMS were developed where the erasure region was broken up into smaller "fields" that could be erased individually without affecting the others. Altering the contents of a particular memory location involved first copying the entire field into an off-chip buffer memory, erasing the field, and then re-writing the data back into the same field, making the necessary alteration to the relevant memory location while doing so. This required considerable computer support, and PC-Based EEPROM flash memory systems often carried their own dedicated microprocessor system. Flash drives are more or less a miniaturized version of this.
The development of high-speed serial data interfaces such as USB for the first time made serially accessed storage memory systems viable, and the simultaneous development of small, high-speed, low-power microprocessor systems allowed this to be incorporated into extremely compact systems. Serial access also greatly reduced the number of electrical connections required for the memory chips, which has allowed the successful manufacture of multi-gigabyte capacities. (Every external electrical connection is a potential source of manufacturing failure, and with traditional manufacturing, a point is rapidly reached where the successful yield approaches zero).
Modern flash memory systems are accessed 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 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.
USB flash drive
A USB flash drive is a NAND-type flash memory data storage device integrated with a USB (universal serial bus) connector. USB flash drives are typically removable and rewritable, much shorter than a floppy disk (1 to 4 inches or 2.5 to 10 cm), and weigh less than 2 ounces (60 g). Storage capacities typically range from 64 MB to 32 GB[1] with steady improvements in size and price per gigabyte. Some allow 1 million write or erase cycles and have 10-year data retention, connected by USB 1.1 or USB 2.0. USB Memory card readers are also available, whereby rather than being built-in, the memory is a removable flash memory card housed in what is otherwise a regular USB flash drive, as described below.
USB flash drives offer potential advantages over other portable storage devices, particularly the floppy disk. They are more compact, faster, hold much more data, have a more durable design, and are more reliable for lack of moving parts. Additionally, it has become increasingly common for computers to ship without floppy disk drives. USB ports, on the other hand, appear on almost every current 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 be faster than an optical disc drive, while storing a larger amount of data in a much smaller space.
With nothing being mechanically driven in a flash drive, the name is something of a misnomer. It is called a "drive" because it appears to the computer operating system (and the user) in a manner identical to a mechanical disk drive, and is accessed in the same way.
A flash drive consists of a small printed circuit board typically in a plastic or metal casing and more recently in rubber casings to increase their robustness. This makes the drive sturdy enough to be carried about in a pocket, for example as a key fob, or on a lanyard. Only the USB connector protrudes, and it is typically protected either by a removable cap or by retracting into the body of the drive. Most flash drives use a standard type-A USB connection allowing them to be connected directly to a port on a personal computer.
To access the data stored in a flash drive, the drive must be connected to a USB port through either a host controller built into a computer, a USB hub, or some other device designed to access the data, such as an mp3 player with a USB-in port. Flash drives are active only when plugged into a USB connection and draw all necessary power from the supply provided by that connection. Some flash drives, however, especially high-speed drives, may require more power than the limited amount provided by a bus-powered USB hub, such as those built into some computer keyboards or monitors. These drives will not work properly unless plugged directly into a host controller (i.e., the ports found on the computer itself) or a self-powered hub.
USB flash drives offer potential advantages over other portable storage devices, particularly the floppy disk. They are more compact, faster, hold much more data, have a more durable design, and are more reliable for lack of moving parts. Additionally, it has become increasingly common for computers to ship without floppy disk drives. USB ports, on the other hand, appear on almost every current 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 be faster than an optical disc drive, while storing a larger amount of data in a much smaller space.
With nothing being mechanically driven in a flash drive, the name is something of a misnomer. It is called a "drive" because it appears to the computer operating system (and the user) in a manner identical to a mechanical disk drive, and is accessed in the same way.
A flash drive consists of a small printed circuit board typically in a plastic or metal casing and more recently in rubber casings to increase their robustness. This makes the drive sturdy enough to be carried about in a pocket, for example as a key fob, or on a lanyard. Only the USB connector protrudes, and it is typically protected either by a removable cap or by retracting into the body of the drive. Most flash drives use a standard type-A USB connection allowing them to be connected directly to a port on a personal computer.
To access the data stored in a flash drive, the drive must be connected to a USB port through either a host controller built into a computer, a USB hub, or some other device designed to access the data, such as an mp3 player with a USB-in port. Flash drives are active only when plugged into a USB connection and draw all necessary power from the supply provided by that connection. Some flash drives, however, especially high-speed drives, may require more power than the limited amount provided by a bus-powered USB hub, such as those built into some computer keyboards or monitors. These drives will not work properly unless plugged directly into a host controller (i.e., the ports found on the computer itself) or a self-powered hub.
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