COMPONENTS OF A COMPUTER: THE MOTHERBOARD

I wanna talk about the computer system; the motherboard to be precise.

First of all, WHAT IS A MOTHERBOARD?

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A motherboard (sometimes alternatively known as the mainboard, system board, baseboard, planar board or logic board) is one of the most essential parts of a computer system which holds and allow communication between many of the crucial electronic components of a computer, including the CPU (central processing unit), memory and connectors for input and output devices. The base of a motherboard consists of a very firm sheet of non-conductive material, typically some sort of rigid plastic. Thin layers of copper or aluminum foil, referred to as traces, are printed onto this sheet. These traces are very narrow and form the circuits between the various components. Unlike a back-plane, a motherboard usually contains significant sub-systems such as the central processor, the chipset's input/output and memory controllers, interface connectors, and other components integrated for general purpose use.

Motherboard specifically refers to a PCB with expansion capability and as the name suggests, this board is often referred to as the "mother" of all components attached to it, which often include peripherals, interface cards, and daughter-cards: sound cards, video cards, network cards, hard drives, or other forms of persistent storage; TV tuner cards, cards providing extra USB or Fire-wire slots and a variety of other custom components.

DESIGN:

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A motherboard provides the electrical connections by which the other components of the system communicate. Unlike a back-plane, it also contains the central processing unit and hosts other subsystems and devices.
A typical desktop computer has its microprocessor, main memory, and other essential components connected to the motherboard. Other components such as external storage, controllers for video display and sound, and peripheral devices may be attached to the motherboard as plug-in cards or via cables; in modern microcomputers it is increasingly common to integrate some of these peripherals into the motherboard itself.
An important component of a motherboard is the microprocessor's supporting chipset, which provides the supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard.

Modern motherboards include:
*Sockets (or slots) in which one or more microprocessors may be installed. In the case of CPUs in ball grid array packages, such as the VIA C3, the CPU is directly soldered to the motherboard.
*Slots into which the system's main memory is to be installed (typically in the form of DIMM modules containing DRAM chips)
*A chipset which forms an interface between the CPU's front-side bus, main memory, and peripheral buses
*Non-volatile memory chips (usually Flash ROM in modern motherboards) containing the system's firmware or BIOS
*A clock generator which produces the system clock signal to synchronize the various components
*Slots for expansion cards (the interface to the system via the buses supported by the chipset)
*Power connectors, which receive electrical power from the computer power supply and distribute it to the CPU, chipset, main memory, and expansion cards. As of 2007, some graphics cards (e.g. GeForce 8 and Radeon R600) require more power than the motherboard can provide, and thus dedicated connectors have been introduced to attach them directly to the power supply.
*Connectors for hard drives, typically SATA only. Disk drives also connect to the power supply.

Additionally, nearly all motherboards include logic and connectors to support commonly used input devices, such as USB for mouse devices and keyboards. Early personal computers such as the Apple II or IBM PC included only this minimal peripheral support on the motherboard. Occasionally video interface hardware was also integrated into the motherboard; for example, on the Apple II and rarely on IBM-compatible computers such as the IBM PC Jr. Additional peripherals such as disk controllers and serial ports were provided as expansion cards.

Given the high thermal design power of high-speed computer CPUs and components, modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat.

FORM FACTOR:

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Motherboards are produced in a variety of sizes and shapes called computer form factor, some of which are specific to individual computer manufacturers. However, the motherboards used in IBM-compatible systems are designed to fit various case sizes. As of 2007, most desktop computer motherboards use the ATX standard form factor — even those found in Macintosh and Sun computers, which have not been built from commodity components. A case's motherboard and PSU form factor must all match, though some smaller form factor motherboards of the same family will fit larger cases. For example, an ATX case will usually accommodate a microATX motherboard.

Laptop computers generally use highly integrated, miniaturized and customized motherboards. This is one of the reasons that laptop computers are difficult to upgrade and expensive to repair. Often the failure of one laptop component requires the replacement of the entire motherboard, which is usually more expensive than a desktop motherboard due to the large number of integrated components and their custom shape and size.

MOTHERBOARD COMPONENTS:

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Listed below are some of the components of a motherboard, also the is the image of an ASUS P5AD2-E motherboard with labels next to each of its major components.

*Expansion slots (PCI Express, PCI, and AGP)
*3-pin case fan connectors
*Back pane connectors
*Heat sink
*4-Pin (P4) power connector
*Inductor
*Capacitor
*CPU Socket
*Northbridge
*Screw hole
*Memory slot
*Super I/O
*Floppy connection
*ATA (IDE) disk drive primary connection
*24-pin ATX power Supply connector
*Serial ATA connections
*Coin cell battery (CMOS backup battery)
*RAID
*System panel connectors
*FWH
*Southbridge
*Serial port connector
*USB headers
*Jumpers
*Integrated circuit
*1394 headers
*SPDIF
*CD-IN

CPU SOCKETS:

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A CPU socket (central processing unit) or slot is an electrical component that attaches to a Printed Circuit Board (PCB) and is designed to house a CPU (also called a microprocessor). It is a special type of integrated circuit socket designed for very high pin counts. A CPU socket provides many functions, including a physical structure to support the CPU, support for a heat sink, facilitating replacement (as well as reducing cost), and most importantly, forming an electrical interface both with the CPU and the PCB. CPU sockets on the motherboard can most often be found in most desktop and server computers (laptops typically use surface mount CPUs), particularly those based on the Intel x86 architecture. A CPU socket type and motherboard chipset must support the CPU series and speed.

INTEGRATED PERIPHERALS:

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With the steadily declining costs and size of integrated circuits, it is now possible to include support for many peripherals on the motherboard. By combining many functions on one PCB, the physical size and total cost of the system may be reduced; highly integrated motherboards are thus especially popular in small form factor and budget computers.

*Disk controllers for a floppy disk drive, up to 2 PATA drives, and up to 6 SATA drives (including RAID 0/1 support)
*Integrated graphics controller supporting 2D and 3D graphics, with VGA and TV output
*Integrated sound card supporting 8-channel (7.1) audio and S/PDIF output
*Fast Ethernet network controller for 10/100 Mbit networking
*USB 2.0 controller supporting up to 12 USB ports
*IrDA controller for infrared data communication (e.g. with an IrDA-enabled cellular phone or printer)
*Temperature, voltage, and fan-speed sensors that allow software to monitor the health of computer components.

PERIPHERAL CARD SLOTS:

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A typical motherboard will have a different number of connections depending on its standard and form factor.

A standard, modern ATX motherboard will typically have two or three PCI-Express 16x connection for a graphics card, one or two legacy PCI slots for various expansion cards, and one or two PCI-E 1x (which has superseded PCI). A standard EATX motherboard will have two to four PCI-E 16x connection for graphics cards, and a varying number of PCI and PCI-E 1x slots. It can sometimes also have a PCI-E 4x slot (will vary between brands and models).

Some motherboards have two or more PCI-E 16x slots, to allow more than 2 monitors without special hardware, or use a special graphics technology called SLI (for Nvidia) and Crossfire (for AMD). These allow 2 to 4 graphics cards to be linked together, to allow better performance in intensive graphical computing tasks, such as gaming, video editing, etc.

TEMPERATURE AND RELIABILITY:

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Motherboards are generally air cooled with heat sinks often mounted on larger chips, such as the Northbridge, in modern motherboards. Insufficient or improper cooling can cause damage to the internal components of the computer, or cause it to crash. Passive cooling, or a single fan mounted on the power supply, was sufficient for many desktop computer CPU's until the late 1990s; since then, most have required CPU fans mounted on their heat sinks, due to rising clock speeds and power consumption. Most motherboards have connectors for additional case fans and integrated temperature sensors to detect motherboard and CPU temperatures and controllable fan connectors which the BIOS or operating system can use to regulate fan speed. Alternatively computers can use a water cooling system instead of many fans.

Some small form factor computers and home theater PCs designed for quiet and energy-efficient operation boast fan-less designs. This typically requires the use of a low-power CPU, as well as careful layout of the motherboard and other components to allow for heat sink placement.

A 2003 study found that some spurious computer crashes and general reliability issues, ranging from screen image distortions to I/O read/write errors, can be attributed not to software or peripheral hardware but to aging capacitors on PC motherboards. Ultimately this was shown to be the result of a faulty electrolyte formulation, an issue termed capacitor plague.

Standard motherboards use electrolytic capacitors to filter the DC power distributed around the board. These capacitors age at a temperature-dependent rate, as their water based electrolytes slowly evaporate. This can lead to loss of capacitance and subsequent motherboard malfunctions due to voltage instabilities. While most capacitors are rated for 2000 hours of operation at 105 °C (221 °F), their expected design life roughly doubles for every 10 °C (18 °F) below this. At 65 °C (149 °F) a lifetime of 3 to 4 years can be expected. However, many manufacturers deliver substandard capacitors, which significantly reduce life expectancy. Inadequate case cooling and elevated temperatures around the CPU socket exacerbate this problem. With top blowers, the motherboard components can be kept under 95 °C (203 °F), effectively doubling the motherboard lifetime.

Mid-range and high-end motherboards on the other hand use solid capacitors exclusively. For every 10 °C less, their average lifespan is multiplied approximately by three, resulting in a 6-times higher lifetime expectancy at 65 °C (149 °F). These capacitors may be rated for 5000, 10000 or 12000 hours of operation at 105 °C (221 °F), extending the projected lifetime in comparison with standard solid capacitors.

AIR POLLUTION AND RELIABILITY:

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High rates of motherboard failures in China and India appear to be due to "sulfurous air pollution produced by coal" that's burned to generate electricity. Air pollution corrodes the circuitry, according to Intel researchers.

BOOTSTRAPPING USING THE INPUT/OUTPUT SYSTEM:

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Motherboards contain some non-volatile memory to initialize the system and load some startup software, usually an operating system, from some external peripheral device. Microcomputers such as the Apple II and IBM PC used ROM chips mounted in sockets on the motherboard. At power-up, the central processor would load its program counter with the address of the boot ROM and start executing instructions from the ROM. These instructions initialized and tested the system hardware, displayed system information on the screen, performed RAM checks, and then loaded an initial program from an external or peripheral device. If none was available, then the computer would perform tasks from other memory stores or display an error message, depending on the model and design of the computer and the ROM version. For example, both the Apple II and the original IBM PC had Microsoft Cassette BASIC in ROM and would start that if no program could be loaded from disk.

Most modern motherboard designs use a BIOS, stored in an EEPROM chip soldered to or socketed on the motherboard, to booting an operating system. Non-operating system boot programs are still supported on modern IBM PC-descended machines, but nowadays it is assumed that the boot program will be a complex operating system such as Microsoft Windows or Linux. When power is first supplied to the motherboard, the BIOS firmware tests and configures memory, circuitry, and peripherals. This Power-On Self Test (POST) may include testing some of the following things:

*Video adapter
*Cards inserted into slots, such as conventional PCI
*Floppy drive
*Temperatures, voltages, and fan speeds for hardware monitoring
*CMOS memory used to store BIOS setup configuration
*Keyboard and Mouse
*Network controller
*Optical drives: CD-ROM or DVD-ROM
*SCSI hard drive
*IDE, EIDE, or Serial ATA Hard disk drive
*Security devices, such as a fingerprint reader or the state of a latching switch to detect intrusion
*USB devices, such as a memory storage device

On recent motherboards the BIOS may also patch the central processor microcode if the BIOS detects that the installed CPU is one for which errata have been published.

cc: https://en.wikipedia.org/wiki/Motherboard
https://study.com/academy/lesson/what-is-a-motherboard-definition-function-diagram.html
https://www.computerhope.com/jargon/m/mothboar.htm