What is USB? How it Works? whats the Uses?

USB provides an expandable, hot-pluggable Plug and Play serial interface that ensures a standard, low-cost connection for peripheral devices such as storage devices, keyboards, joysticks, printers, scanners, modems, and digital cameras.


USB is natively supported in almost all desktop operating systems (Windows, Linux) while other embedded operating systems or firmware that need USB support require a dedicated USB stack,


Whether you refer to it as a pen drive, jump drive, thumb drive, key drive, or memory stick, you have to admit, the USB Flash drive is pretty darn cool. Just stick it into the USB port on your computer and within a few seconds a new drive appears on your desktop. So simple and so easy. What makes them so good is that they have a spate of desirable features such as no need for batteries, solid state storage, good transfer speeds, durability, portability, and expected data retention of ten years. All of these features allow these little babies to practically replace the floppy, the Zip disk, and the CD-R/RW all in one fell swoop.


Unfortunately, when comparing USB Flash drives side-by-side in a computer or electronics store, it can be awfully difficult to decide which is best for you just by looking at the drive and the packaging. It would be easy to make an assumption that all drives are pretty much the same and that shopping for the best price is the smartest way of deciding. We are here to inform you that USB Flash drives are not a commodity and can be very unique offerings. As you will soon find out, some are clearly better than others while others come bundled with nifty features that can really make your day. In short, not all flash drives are created equal.


USB devices can provide a remote wakeup function for the computer. The USB root hub in the computer is set to support remote wakeup whenever a device is attached to or disconnected from the bus. The keyboard that comes with the computer uses this method to wake the computer on a key press.

USB Storage DevicesThe iMac can boot from a USB storage device that follows the USB Mass Storage Class specification.

Class drivers are software components that are able to communicate with many USB devices of a particular kind. If the appropriate class driver is present, any number of compliant devices can be plugged in and start working immediately without the need to install additional software. The Mac OS for the iMac includes USB Mass Storage Support 2.0, a class driver that supports devices that meet the USB Mass Storage Class specification.

USB ControllerThe iMac uses an Open Host Controller Interface (OHCI) controller for USB communication. Some early USB devices (most notably keyboards) can't interoperate with an OHCI controller. Those devices are not supported by the Macintosh USB system software.