Almost all motherboards adjustment shall be made through the BIOS. Starting from changing the settings on the hard drive to change the CPU speed. But a few years ago, the jumper is the only way to change the main options motherboard.
Jumper is located on the motherboard, can be a switch or 'plastic cap' that covers some of the pins. To change the setting to raise or lower the switch. while the form of 'cap' is operated by the road to take or remove his hat, which changed the flow of electricity.
Jumper very rare now, but still needed by the device's hard drive and optical drives. Usually, to change the settings of the drive: master or slave.