The Universal Serial Bus (USB) was introduced as a new connectivity interface in the personal computers in the late nineties as the prevalent serial posts and parallel ports were too slow for high speed communication. Standardization of the UBS ports made it possible for a huge array of equipment to be connected with the personal computer. USB pen drives are portable storage devices having multiple usages with connectivity to the personal computer through the standard USB or the newly developed mini-USB which is a miniature version of the Standard USB port to save space on small devices. USB pen drives employ flash memory chips to mimic the working of hard disks. These behave exactly like a hard disk albeit without any moving parts. Pen drives have evolved so much that they have become the equivalent of multi utility vehicles amongst the flash drives available in the market.

Till 2006 the 16 gigabyte pen drives were the most commonly sold pen drives, but the year 2007 has seen the capacities going up to 80 gigabytes and with the computer mother boards now supporting boot from USB drives it is now possible to install the whole operating systems in a ubiquitous pen drive together with your frequently required applications and what you have is a your own hard disk loaded with your own operating system and you get your own working environment which you can carry in the pocket of your shirt.

Windows XP in a computer system recognizes any pen drive on connection as it does not require any additional drivers to be installed making pen drives the ideal choice for transferring data and files from one computer to another. Now some manufacturers have introduced printers which can print files directly off a pen drive with out the need of a computer. The pen drives have revolutionized the removable storage medium.