MOTHERBOARD (Main board)

MOTHERBOARD (Main board): A motherboard, also known as a main board, mainboard, logic board or system board, and sometimes abbreviated as mobo, is the central or primary circuit board making up a complex electronic system, such as a computer.

The best way to describe the motherboard goes along well with my human body analogy that I used for the CPU. The CPU is the brain, and the motherboard is the nervous system.

A motherboard by itself is useless, but a computer has to have one to operate. The motherboard's main job is to hold the computer's microprocessor chip and let everything else connect to it. Everything that runs the computer or enhances its performance is either part of the motherboard or plugs into it via a slot or port.

Form Factor

The shape and layout of a motherboard is called the form factor. The form factor affects where individual components go and the shape of the computer's case. There are several specific form factors that most PC motherboards use so that they can all fit in standard cases.

The form factor is just one of the many standards that apply to motherboards. Some of the other standards include:

• The socket for the microprocessor determines what kind of Central Processing Unit (CPU) the motherboard uses.
• The chipset is part of the motherboard's logic system and is usually made of two parts -- the northbridge and the southbridge. These two "bridges" connect the CPU to other parts of the computer.
• The Basic Input/Output System (BIOS) chip controls the most basic functions of the computer and performs a self-test every time you turn it on. Some systems feature dual BIOS, which provides a backup in case one fails or in case of error during updating.
• The real time clock chip is a battery-operated chip that maintains basic settings and the system time.

Below are the different types of form factors:

• PC/XT - Although it wasn't the first PC, it had many features that were not available with previous PC designs. One such feature was that it was the first computer to have a hard drive. It also had a large computer motherboard that was installed into a full size horizontal or desktop case.
• Full-Size AT - The full-size AT mainboards were large in order to accommodate a lot of circuitry and could be installed in full-size AT desktop and tower cases. At present, full-size AT motherboards are no longer produced.
• Baby-AT - Between 1983 to 1986, Baby-AT form factor became the most popular computer motherboard because it was able to fit into a number of different case designs. Today, you may still be able to get motherboards of this design. In 1996, the Baby-AT was replaced by the ATX design.
• LPX - This board was a semi-proprietary motherboard design which was difficult to repair and upgrade. Also, replacement parts for upgrades were expensive thus making it more economical to purchase a brand new non-proprietary design.
• ATX - This design improved upon the Baby-AT and the LPX designs. Its physical dimensions are approximaely 12" x 9.6". This design is not compatible with AT designs because the motherboard is turned sideways in the case and has a different power supply connector.
• Micro ATX - This is a smaller version of the ATX form factor. Its physical dimensions are approximately 9.6" x 9.6".

All form factors that precede the ATX are now obsolete. A new form factor called BTX is now emerging. There will be three basic sizes:

• picoBTX - 7.9" x 10.4".
• microBTX - 10.3" x 10.4".
• BTX - 12.7" x 10.4".

The slots and ports found on a motherboard include:

• Peripheral Component Interconnect (PCI)- connections for video, sound and video capture cards, as well as network cards.
• Accelerated Graphics Port (AGP) - dedicated port for video cards.
• Integrated Drive Electronics (IDE) - interfaces for the hard drives.
• Universal Serial Bus or FireWire - external peripherals.
• Memory slots

Some motherboards also incorporate newer technological advances:

• Redundant Array of Independent Discs (RAID) controllers allow the computer to recognize multiple drives as one drive.
• PCI Express is a newer protocol that acts more like a network than a bus. It can eliminate the need for other ports, including the AGP port.
• Rather than relying on plug-in cards, some motherboards have on-board sound, networking, video or other peripheral support.