A small, plastic-covered metal block that is pushed onto two pins to close a circuit. An alternative to the DIP switch, the jumper is a less costly on/off switch found on motherboards and peripheral devices for one-time configuration. Although jumpers exist on modern computers, especially on hard disk drives, they were more prevalent in the early days of personal computers. Configuration of the hardware via software eliminated the use of many jumpers. See DIP switch and jumperless.