A motherboard =  central printed circuit board (PCB) =  mainboard =  system board =  Applelogic board = mobo.

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.

The essential motherboard make-up includes the chipset (known as the “glue logic“), some code in ROM and the various wired interconnections between the components know as buses.
The chipset is fundamental, and controls how the motherboard interacts
with everything else in the system. A good chipset can be more
important than the power of CPU or the amount of RAM. The ROM code
includes the BIOS, which has user-changeable options for how the
motherboard operates with integral and connected devices.

 Motherboard Standard  :

1-Form factor is the shape and layout of a motherboard ,The form factor affects where individual components go and the shape of the computer’s case.

2-  Socket for the microprocessor determines what kind of Central Processing Unit (CPU) the motherboard uses.

3- 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.

4- (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.

5-The real time clock chip is a battery-operated chip that maintains basic settings and the system time.

The slots and ports found on a motherboard include:

1- (PCI)- connections for video, sound and video capture cards, as well as network cards

2-Accelerated Graphics Port (AGP) – dedicated port for video cards.

3-Integrated Drive Electronics (IDE) – interfaces for the hard drives

4-Universal Serial Bus or FireWire – external peripherals

5-Memory slots

Basic Input/Output System (BIOS) designed to be the first code run by a PC when powered on. The initial function of the BIOS is to identify, test, and initialize system devices such as the video display card, hard disk, and floppy disk and other hardware. This is to prepare the machine into a known state, so that software stored on compatible media can be loaded, executed, and given control of the PC.This process is known as booting, or booting up, which is short for bootstrapping.

The first thing the BIOS does is check the information stored in a tiny (64 bytes) amount of RAM located on a complementary metal oxide semiconductor (CMOS) chip. The CMOS Setup provides detailed information particular to your system and can be altered as your system changes. The BIOS uses this information to modify or supplement its default programming as needed.

After checking the CMOS Setup and loading the interrupt handlers, the BIOS determines whether the video card is operational.

Next, the BIOS checks to see if this is a cold boot or a reboot.

If it is a cold boot, the BIOS verifies RAM by performing a read/write test of each memory address. It checks the PS/2 ports or USB ports for a keyboard and a mouse. It looks for a peripheral component interconnect (PCI) bus and, if it finds one, checks all the PCI cards. If the BIOS finds any errors during the POST, it will notify you by a series of beeps or a text message displayed on the screen. An error at this point is almost always a hardware problem.

BIOS then displays some details about your system.

and system start begin