Wednesday, August 8, 2012

Identifying Motherboard Hardware Parts and its Function

The motherboard is considered as the main circuit of the computer, it contains the connectors for attaching additional boards. Typically, the motherboard contains the CPU, BIOS, memory, mass storage interfaces, serial and parallel ports, expansion slots, and all the controllers required to control standard peripheral devices, such as the display screen, keyboard, and disk drive. Collectively, all these chips that reside on the motherboard are known as the motherboard's chipset. You must familiarize the motherboard parts and its function since this is needed to pass the TESDA NC II Computer Servicing Exam. 

Parts of the Mother Board


BIOS or Basic Input Output System

A main function of the BIOS is to give instructions for the power-on self test (POST).This self test ensures that the computer has all of the necessary parts and functionality needed to successfully start itself, such as use of memory, a keyboard and other parts. If errors are detected during the test, the BIOS instruct the computer to give a code that reveals the problem. Computer Error codes are typically a series of beeps heard shortly after startup.

Carbon Metal–Oxide–Semiconductor (CMOS) - is a technology for making integrated circuits. CMOS technology is used in microprocessors, microcontrollers, static RAM, and other digital logic circuits. CMOS technology is also used for a wide variety of analog circuits such as image sensors, data converters, and highly integrated transceivers for many types of communication. Frank Wanlass successfully patented CMOS in 1967 (US Patent 3,356,858).

CMOS Battery - Is a button cell battery that gives power to CMOS so that the Bios setting is retain when the PC is turn off.

Chipset - Refers to a specific pair of chips on the motherboard: the NORTHBRIDGE and the SOUTHBRIDGE.The northbridge links the CPU to very high-speed devices, especially main memory and graphics controllers.

The southbridge connects to lower-speed peripheral buses (such as PCI or ISA). In many modern chipsets, the southbridge actually contains some on-chip integrated peripherals, such as Ethernet, USB, and audio devices. A chipset is usually designed to work with a specific family of microprocessors. Because it controls communications between the processor and external devices, the chipset plays a crucial role in determining system performance.

Types of Processor Sockets or Slots

PGA Processor Slot
A CPU socket or CPU slot is an electrical component that attaches to a printed circuit board (PCB) and is designed to house a CPU (also called a microprocessor). CPU socket structure is largely dependent on the packaging of the CPU it is designed to house. Most CPUs are based on the pin grid array (PGA) architecture in which short, stiff pins are arranged in a grid on the underside of the processor are mated with holes in the socket. To minimize the risk of bent pins, zero insertion force (ZIF) sockets allow the processor to be inserted without any resistance and then lock in place with a lever or latch mechanism.

SLOT TYPE CPU slot - are single-edged connectors similar to expansion slots, into which a PCB holding a processor is inserted. Slotted CPU packages offered two advantages: L2 cache memory size could be packaged with the CPU rather than the motherboard and processor insertion and removal was often easier. However, they proved to have performance limitations and once it was possible to place larger cache memory directly on the CPU die the industry reverted back to sockets.

Land grid array (LGA) - packages have started to supplant PGA with most modern CPU designs using this scheme. The term LGA "socket" is actually a bit of a misnomer. With LGA sockets, the socket contains pins that make contact with pads or lands on the bottom of the processor package.

Types of Memory Socket or Slot

Memory Socket or Slot - is commonly refers to the slot in a motherboard were the extended memory modules are installed.

SIMM (Single-inline-memory module) slot, 72 pins

DIMM (Dual-inline-memory modules) slot. SDR (Single Data Rate) DIMM slot. 168 edge contacts.
DDR (Dual/Double Data Rate) DIMM slot. 184 edge contacts (DDR 1)
DDR (Dual/Double Data Rate) DIMM slot. 240 edge contacts (DDR 2 / 3)

SODIMM (SO-DIMM is short for Small Outline DIMM ) Slot A 72-pin and 144-pin configuration. SO-DIMMs are commonly utilized in laptop computers.

Computer System Expansion Slots

The Expansion slot is a type of slot that connects an expansion bus (Adapter card), which allows the processor to communicate with peripheral attached to the adapter card. Data is transmitted to the memory or the processor travels from the expansion slot via the expansion bus and the system bus.

ISA Slot
ISA SLOT - Industry Standard Architecture, is an a 8 bit and 16 bit wide bus, and runs at 4.77 mhz. The ISA bus was developed by a team lead by Mark Dean at IBM as part of the IBM PC project in 1981. It was originated as an 8-bit system and was extended in 1983 for the XT system architecture. The newer 16-bit standard, the IBM AT bus, was introduced in 1984.

PCI - Slot
PCI SLOT - Peripheral Component Interconnect is a specification that defines a 32-bit data bus interface. PCI is a standard widely used by expansion card manufacturers.

AGP - Slot
AGP SLOT - Accelerated Graphics Port, also called Advanced Graphics Port, often shortened to AGP it is a high-speed point-to-point channel for attaching a graphics card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. AGP controller is only capable of controlling a single device.
AMR SLOT - Audio Modem Riser,  Is a riser card that supports sound or modem function.

ACR SLOT - Advance Communication Riser, this type of slot is for communication and audio subsystem. The slot supports modem, audio, LAN, and Home Phoneline Networking Alliance (HPNA) or Home Networking cards.

CNR SLOT - Communications network riser, this connector supports specially designed network, audio, or modem riser cards, main processing is done through software and controlled by the motherboard’s system chipset.

PCI - Express
PCI –E - is a computer expansion card interface format introduced by Intel in 2004. It was designed to replace the general purpose PCI expansion bus.

  • PCIe 1.1 (the most common version as of 2007) each lane carries 250 MB/s.
  • PCIe 2.0 doubles the bus standard's bandwidth from 2.5 Gbit/s to 5 Gbit/s, meaning a x32 connector can transfer data at up to 16 GB/s in each direction.
  • PCI Express 3.0 will carry a bit rate of 8 giga transfers per second.

IDE - Controller
IDE CONTROLLER - Integrated Drive Electronics, Parallel ATA (PATA) is an interface standard for the connection of storage devices such as hard disks, solid-state drives, and CD-ROM drives in computers. It uses the underlying AT Attachment and AT Attachment Packet Interface (ATA/ATAPI) standards

FDD - Controller
FDD CONTROLLER - Floppy Disk Drive, an onboard floppy drive controller which make your Floppy Disk Drive operational.

SATA - Controller
SATA CONTROLLER - Serial Advanced Technology Attachment is a computer bus primarily designed for transfer of data between a computer and storage devices (like hard disk drives or optical drives).

  • SATA 1.5 Gbit/s
  • SATA 3.0 Gbit/s
  • SATA 6.0 Gbit/s

Types of Power Supply Terminal

ATX - Power Connector

These connectors are for power supply, the power supply plugs are designed to fit these connectors in only one orientation.

  • AT / ATX
  • Auxiliary power

FRONT PANEL CONNECTOR / SYSTEM PANEL CONNECTOR - This connector attaches the switches and indicators.
Front Panel Connectors

  • Power switch (PWRSW) power-on the system unit
  • Reset switch (RESET) – Resets the system unit
  • Power / System LED – The system power LED lights up when system is powered up / Power indicator
  • Hard disk drive LED (HDDLED) –The HDD LED lights up(Blinks) during harddisk activity.


I/O Ports are type of interface which a peripheral attaches to or communicates with the system unit so the peripheral can send data to or receive information from the computer.

  • Keyboard / mouse
  • Monitors, projector
  • Printers, flatbed scanner
  • External storage devices, external modems
  • Headsets, microphones, game pads

I/O Ports
PS2 PORT - Personal system 2, are based on IBM Micro Channel Architecture, it is a 6-pin connector.This type of architecture transfers data through a 16-bit or 32-bit bus.

  • Keyboard
  • Mouse

LPT PORT or PARALLEL PORT - Line Printer Port, This is a 25-pin port that connects a parallel printer, a flatbed scanner and used as a communication link for null modem cables.

SERIAL PORT or COM PORT - is a logical device name used by to designate the computer serial ports. A 9-pin connector used by pointing devices, modems, and infrared modules can be connected to COM ports.

USB PORT - Universal Serial Bus, a 4-pin serial cable bus that allows up to 127 plug-n-play computer peripherals. This allows attaching or detaching of peripherals while the host is in operation. Supports synchronous and asynchronous transfer types over the same set of wires up to 12Mbit/sec. USB 2.0 provides 40 times the transfer rate compared to USB 1.0 and competes with the 1394 standard.As of today we now have USB 3.0.

GAME/MIDI PORT  - This connector supports a Joystick or a Game Pad for playing games, and MIDI   Devices for playing or editing audio files.

LAN PORT - Used for Networking

AUDIO/SOUND port - Used for sound output, Line inputs and Microphone inputs