The Universal Serial Bus Flash drive was first of all introduced in 1998. In 2000, the first USB flash drives were commercially sold by Trek Technology and IBM and its capacity was only 8 MB. The USB flash derive is a small storage device and is connected to the computer via USB port and fulfills the role of floppy disks, CD-RWs and other removable storage devices. Now depending upon the model capacity a single drive can store from 64MB to 256GB.