USB, short for Universal Serial Bus, is a port used for the connection of a wide variety of computer devices. The standard of USB is designed to be split to connect as many as 127 peripherals from one port. Supporting transfer rates of 12 Mbps, the USB standard was first used in commercial machines in 1996. In 1998 the iMac´s release gave a great boost to the trend of integration of USB ports into computers. The USB port not only is used where serial and parallel ports were once used, but it also allows plug-and-play installation of hardware and hot swapping. Whereas before the advent of the USB port a hardware peripheral would need to be connected before the computer was turned on in order to function properly, USB devices, with a few exceptions, have full functionality when plugged in to a running computer.