THe CMOS chip contains programs that the BIOS program accesses to carry out the CMOS instructions contained within the BIOS setup utility settings.
In other words, the BIOS uses CMOS to carry out lines of code contained on the CMOS chip (burned in at the factory), and then after the POST, the bootstrap portion of the operating system starts up the operating system.
All this is done from the BIOS program. The CMOS Setup Utility screen allows you to make changes to the CMOS configuration obviously, but it's the BIOS that conducts the earlier business of the startup of a PC.
And like CVB said, the chipset is the North and SouthBridges. They are made by the same manufacturer as a set. Intel makes a lot, I think VIA is another manufacturer as well.
The two chips in the chipset are made as a tandem, mostly because of their inherant characteristics that they must work together, and are designed to do so. So they are usually made by the same manufacturer because they must work so closely with each other. The CPU "talks" with the chipset and other devices via the system's address buses and external data buses.
Originally Posted by oldskool
All this is done from the BIOS program....
And by this ^^^^^^^ I mean to say that the CMOS Setup Utility is a program whose screen is found within the BIOS settings that you can access just before booting the OS by hitting a particular hotkey, such as DEL, or F1 or something like that depending on the PC manufacturer in question. They use different BIOS chip makers. The BIOS is contained on a chip as well (oddly enough called the BIOS or system chip).