A USB flash drive is a portable USB (Universal Serial Bus) flash memory device for storing and transferring audio, video, and data files from a computer. As long as the desktop or laptop has a USB port and the flash drive is compatible with the operating system, it should be easy to transfer data from the hard drive to the device, and to another computer, in a matter of minutes. The drive’s name comes from the fact that many have a retractable port connector, like a pen, and are small enough to fit in a pocket. Other names include flash drive, auxiliary drive, and flash drive.
A flash drive usually has a large storage capacity and offers fast data transfers.
how to use it
Using a USB stick is simple: the user inserts one end of the drive, which is equipped with a USB connector, into the USB port of a desktop or laptop computer and activates it. Once the drive is active, files can be dragged and dropped or copied and pasted into memory. The process is usually no more difficult than attaching files to an email or copying files to a disk, mp3 player, or other storage device.
The pen drive is considered an improvement over older floppy disks.
There are many different computer operating systems in use today, so most manufacturers configure their flash drives to work with a variety of systems. Before purchasing any portable storage device, the consumer should read the packaging carefully to ensure that it will work with their computer system. Often, even users running older operating systems can find compatible storage devices as long as those computers have a USB port.
How does it work
Technicians classify flash drives as NOT AND, also called NAND, gate-style data storage devices. This technology works by storing data in blocks rather than randomly; as such, it doesn’t work the same way as a computer’s main memory systems: read-only memory (ROM) and random-access memory (RAM). Using blocks instead of allowing random access allows the drive to store more information and to do so at a lower cost.
transfer speeds
The actual transfer speed depends on several factors, such as how fast the computer reads from and writes to the device. In general, the advertised speed of a flash drive is the read speed because it is faster than the speed at which data can be written to it. Manufacturers typically list speed in megabytes per second (MB/s). The age of the drive and how it is used, such as writing and deleting small files, also affects transfer speed.
Benefits
Packed with a large amount of memory, the flash drive is often considered an improvement over both older floppy disks and more modern compact discs. They can transfer data much faster than these older technologies. Because they are solid state with no moving parts, flash drives generally last longer and the data stored on them is more secure. Depending on storage size, flash drives can be anywhere from 128MB to 32GB or more; by comparison, a standard CD-ROM contains about 700 MB of data.
Even a flash drive with relatively low storage capacity tends to provide plenty of space for all types of files. Any file that can be stored on a computer’s hard drive can usually be copied to a flash drive, provided there is enough memory. There are also programs that can be run directly from the drive, without the need to install them on the computer first.
limitations
Flash drives have some limitations, including the number of times they can be used. Each drive has a limited number of program erase cycles (P/E cycles), which is the act of placing files on the drive and erasing them. Typically, the device can go through 100,000 P/E cycles before the integrity of the drive is compromised and files become corrupted.
Another limitation concerns the way manufacturers build devices. The NAND gate style allows the user to program or read the data one byte or word at a time, but erases the data in blocks. When only small amounts are deleted, the storage capacity is reduced.
The NAND gate style device can also cause data loss due to the way the information is accessed. Reading data in one cell can trigger changes in surrounding cells. Typically, a user must read the cell thousands of times before this occurs, however, and periodically retyping surrounding cells can prevent this problem.
The computer chip in the drive can also wear out, causing the device to run more slowly. The NAND gate-style method of programming and deleting files that are smaller than a block can also slow things down. This can cause the device to mark some blocks as bad, even though they are not completely full; attempting to read bad blocks and reallocate them can slow down the speed with which the device works.
The standard CD-ROM contains about 700 MB of data.
