A basic input/output system (BIOS) jumper is a small device used to configure specific settings within the BIOS of a computer. The jumper is attached to a series of metal pins on a computer motherboard, which completes an electrical circuit and configures the appropriate setting. A BIOS jumper can be used in cases of a lost BIOS password or a corrupted BIOS update.
BIOS software is stored on a computer’s motherboard, and it runs when the computer is first turned on. This software loads an operating system and controls certain hardware settings. The BIOS can be updated, and most types of BIOS software can be protected by a password.
A BIOS jumper can be found inside most computers. The jumper itself is made of conductive material such as metal, and it usually is covered in a plastic coating. During normal operations, the jumper remains in its factory-set position.
If a user has forgotten the BIOS password, a BIOS jumper can be used to reset it. The physical location of the jumper varies depending on the motherboard, but it usually is found near a flat, round battery. It’s best for users to refer to the motherboard’s manual for the location, because it will often include a helpful picture or diagram.
In order to reset the BIOS, the jumper must be removed from its normal position and placed into the reset or clear position. Some motherboards will label the position. Common labels include CLR for "clear", PWRD for "password", RESET or some combination of these phrases. Again, the motherboard's manual frequently will contain pictures or diagrams of the different jumper positions.
The small size of a BIOS jumper means that it can be tricky to manipulate. Many users prefer to use a pair of pliers or tweezers to move the jumper. A computer always should be turned off and unplugged when one is working with internal components.
A BIOS jumper also might have a position for something called BIOS recovery mode. This is useful if an update made the computer unable to boot. In some cases, this requires recovery software loaded on a floppy disk, compact disc or flash drive.
Some motherboards also implement security features to prevent malicious software from modifying the BIOS. These features require a BIOS jumper to be set to a different position before the BIOS can be updated. The jumper must be moved back into its original position after the update is applied.