What is a Motherboard?
Motherboard is the most important component in any personal computer. It contains almost every important elements of the computer. Sometimes instead of the calling it “motherboard”, IBM refers to is as “system Board” or “ Planner Board” , some other manufacturer refer to this as the “Logic Board”.
The motherboard is the main circuit board inside the PC which holds the processor, memory and expansion slots and connects directly or indirectly to every part of the PC. It’s made up of a chipset(known as the “glue logic”), some code in ROM and the various interconnections or buses.

The original PC had a minimum of integrated devices, just ports for a keyboard and a cassette deck (for storage). Everything else, including a display adapter and floppy or hard disk controllers, were add-in components, connected via expansion slots.

1995 - I/O ports and disk controllers were often mounted on expansion
cards. Other components - typically graphics, networking,
SCSI and sound - usually remain separate.

Consequently, those parts of the system whose specification changes fastest - RAM, CPU and graphics - tend to remain in sockets or slots for easy replacement. Similarly, parts that not all users need, such as networking or SCSI, are usually left out of the base specification to keep costs down.

The basic changes in motherboard form factors over the years are covered later in this section - the diagrams below provide a detailed look at the various components on two motherboards. The first a Baby AT design, sporting the ubiquitous Socket 7 processor connector, circa 1995. The second is an ATX design, with a Pentium II Slot 1 type processor connector, typical of motherboards on the market in late 1998.

Baby AT Design

ATX Design
Motherboard development consists largely of isolating performance-critical components from slower ones. As higher speed devices become available, they are linked by faster buses -and the lower-speed...