The USB Flash device has 2 chips. One the controller which connect directly to the USB connector, and the others standard flash device. It has very few components and compost mainly of resistors and capacitors. A green LED is provided to indicate controller’s activity. It has also got a write protect on/off switch.
If you happened to own a computer a decade ago, they used to come with an array of connectors. There were serial ports, parallel ports, infra-red ports, audio/speaker connections, and many other ports. These ports were mainly used to connect printers, web cameras, head phones, scanners etc. And the worst part is that they are not plug and play. You need to install drivers to work with them. More over connectors were not compatible with products of different companies.
With the advent of USB, Now most of the products are having USB as connector and the popular one is USB Flash drive. Computers access modern flash memory systems very much like hard disk drives, where the controller system has full control over where information is actually stored. USB flash drives are often used for the same purposes for which floppy disks or CD-ROMs were used. They are smaller, faster, have thousands of times more capacity, and are more durable and reliable because of their lack of moving parts. Until approximately 2005, most desktop and laptop computers were supplied with floppy disk drives, but floppy disk drives has been abandoned in favor of USB ports.
The first ever Flash memory is (as per sources) 128KB drive for US $45(Rs2000) back in 2002. And today 64GB pen drive for rupees 7000. Prices have come down a lot with in last few years. My latest pen drive weighs less than 30 grams. File transfer speeds vary considerably and should be checked before purchase. Speeds may be given in Mbyte per second, Mbit per second or optical drive multipliers such as “180X” (180 times 150 KiB per second). Typical fast drives claim to read at up to 30 megabytes/s (MB/s) and write at about half that speed. This is about 20 times faster than older “USB full speed” devices which are limited to a maximum speed of 12 Mbit/s (1.5 MB/s).