BIOS - Basic Input Output System

What is the Basic Input Output System for:
    Basic Input Output System. This controls all the lower functionality of the PC and all the devices attached to the PC. The main part of the BIOS is hard-wired, the instructions are etched in so that no info is lost when the PC is off.
    The Basic Input Output System as previously said controls all the lower functions such as various timings for memory, graphics and overall control of all devices attached to or present on-board the motherboard..
    A BIOS can be upgraded, by a program writing new instructions to the hard drive which the BIOS itself reads and carries out. Don't upgrade a it unless you are absolutely sure of what you are doing - if in doubt DON'T DO IT.
    There is an associated utility which runs with the BIOS and this is called the CMOS The name comes from the type of semi-conductors used, in this case, Complementary Metal Oxide Semiconductor. This type of conductor can store data and therefore the user can make changes to the CMOS by using the SETUP utility when the PC first starts up. The CMOS data would be lost on turning off the PC except for the fact that a small voltage from a battery on the motherboard, keeps the data alive. If you mess about with the CMOS 'setup', all is not lost because you can restore defaults. NEVER put a password on the Setup, you might forget it and not be able to get in to the BIOS at a later stage to upgrade/reconfigure.