One of the central functions of the motherboard is the BIOS. The BIOS or Basic Input and Output System contains the programming used to control the keyboard, disk drives, monitor display, and data communications, as well as a few miscellaneous hardware-related actions. The BIOS servers to interface between the PC's hardware and the operating system; monitors the hardware settings, and controls the boot sequence of the PC.

     The BIOS code is installed on the motherboard in a ROM chip. All microprocessors look in the same physical location for their first instruction. This location is the first location of the BIOS. That first instruction is called the jump instruction. The jump instruction of the BIOS program is located at address FFFF0h of conventional memory.

     The BIOS ROM is installed in a motherboard socket and is easily found because of its shiny foil label that identifies its version, date of manufacture, and the name of the manufacturer. If the BIOS ROM chip is updatable with software procedures called flashing, the version reported on the chip may be lower than the actual version in the chip.

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