Everything you wanted to know about a motherboard – II

BIOS: The motherboard basic input/output system (BIOS), also called the system BIOS, is considered to be the heart of the computer because it controls communications between computer hardware and the operating system. System BIOS is also referred to as ROM BIOS because the code is contained in a non-volatile, read-only memory (ROM) chip. As opposed to typical memory chips, non-volatile memory does not lose its contents when electricity is removed, making the chip suitable for storing data for many years. The system BIOS contains a software instruction set called firmware. Firmware provides the basic input/output instructions to boot the computer and handles several important functions including identifying hardware currently installed in the PC, determining which device will boot the PC, and installing basic drivers for the keyboard, video, and disk drives prior to the operating system loading.
Complementary Metal Oxide on Semiconductor (CMOS): CMOS is a chip that stores clock settings, the current system configuration data as discovered by a standard Power-On Self Test (POST) or defined by the setup program, and the Plug and Play settings. Located on the motherboard, CMOS is volatile and requires battery power to maintain the CMOS memory and system time whether the PC is on or off. Battery power comes from one of the following:
· Coin-type watch battery (commonly used)
· Brick/Barrel type battery
· Capacitor, an electrical component that holds a charge
Data stored in the CMOS chip is accessed by the system BIOS and also includes configurable settings such as boot sequence, CPU clock speed, and power management.

Chipset: The chipset controls the flow of information between various components of the motherboard. The chipset on a modern PC contains two or three separate chips and older PCs had as many as five chips. The largest chip is called the North Bridge; the smaller chip is called the South Bridge. The chipset controls many different components of the system including:
· CPU
· Cache
· Main memory
· Peripheral Component Interconnect (PCI) bus
· Industry Standard Architecture (ISA) bus
· Various system resources
In addition, the chipset defines the various functions the system will support including:
· Defines Front-side Bus (FSB) speed (from 66MHz to over 1000MHz)
· Supports Accelerated Graphics Port (AGP) video cards
· Defines the minimum and maximum processor speed the motherboard can handle
The major chipset manufacturers are Intel, Apollo, VIA, and SIS.