System Board
The system board is also called the motherboard, main-board, planar board, or logic board.
Prior to the advent of the microprocessor, a computer was usually built in a card-cage case or mainframe with components connecting to it by a back plane. It usually was consisting of a set of slots themselves connected with wires. The Central Processing Unit, memory and peripherals were housed on individual printed circuit boards which plugged into the back plate.
In the late 1980s, motherboards began to include single ICs (also called Super I/O chips) capable of supporting a set of low-speed peripherals: keyboard, mouse, floppy disk drive, serial ports, and parallel ports. By the late 1990s, many personal computer motherboards supported a full range of audio, video, storage, and networking functions without the need for any expansion cards at all.
The early pioneers of motherboard manufacturing were Micronics, Mylex, AMI, DTK, Hauppauge, Orchid Technology, Elitegroup, DFI, and a number of Taiwan-based manufacturers. The most popular computers such as the Apple II and IBM PC published schematic diagrams and other documentation which permitted rapid reverse-engineering and third-party replacement motherboards.
Prior to the advent of the microprocessor, a computer was usually built in a card-cage case or mainframe with components connecting to it by a back plane. It usually was consisting of a set of slots themselves connected with wires. The Central Processing Unit, memory and peripherals were housed on individual printed circuit boards which plugged into the back plate.
In the late 1980s, motherboards began to include single ICs (also called Super I/O chips) capable of supporting a set of low-speed peripherals: keyboard, mouse, floppy disk drive, serial ports, and parallel ports. By the late 1990s, many personal computer motherboards supported a full range of audio, video, storage, and networking functions without the need for any expansion cards at all.
The early pioneers of motherboard manufacturing were Micronics, Mylex, AMI, DTK, Hauppauge, Orchid Technology, Elitegroup, DFI, and a number of Taiwan-based manufacturers. The most popular computers such as the Apple II and IBM PC published schematic diagrams and other documentation which permitted rapid reverse-engineering and third-party replacement motherboards.
Overview
What it is
A motherboard provides the electrical connections by which the other components of the system communicate. Unlike a back plane, it connects the central processing unit and hosts other subsystems and devices.
Usually the microprocessor, main memory, and other essential components are 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 more modern computers it’s increasingly common to integrate some of these peripherals into the motherboard.
An important component of a motherboard is the microprocessor's supporting chip set. This chip set determines the features and capabilities of the motherboard.
Modern motherboards include, at a minimum sockets (slots), the CPU, slots for the system's main memory, a chip set which forms an interface between the CPU's front-side bus, main memory, and peripheral buses, non-volatile memory chips containing the system's firmware or BIOS, a clock generator to synchronize the various components, slots for expansion cards, power connectors, logic and connectors to support commonly used input devices, and occasionally video interface hardware
Modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat.
CPU sockets
A CPU socket 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, and most importantly, forming an electrical interface both with the CPU and the PCB.
A motherboard provides the electrical connections by which the other components of the system communicate. Unlike a back plane, it connects the central processing unit and hosts other subsystems and devices.
Usually the microprocessor, main memory, and other essential components are 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 more modern computers it’s increasingly common to integrate some of these peripherals into the motherboard.
An important component of a motherboard is the microprocessor's supporting chip set. This chip set determines the features and capabilities of the motherboard.
Modern motherboards include, at a minimum sockets (slots), the CPU, slots for the system's main memory, a chip set which forms an interface between the CPU's front-side bus, main memory, and peripheral buses, non-volatile memory chips containing the system's firmware or BIOS, a clock generator to synchronize the various components, slots for expansion cards, power connectors, logic and connectors to support commonly used input devices, and occasionally video interface hardware
Modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat.
CPU sockets
A CPU socket 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, and most importantly, forming an electrical interface both with the CPU and the PCB.
Temperature and reliability
Motherboards are generally air cooled with heat sinks mounted on larger chips, such as the Northbridge. Insufficient or improper cooling can cause damage to the internal components of the computer and cause it to crash. Newer motherboards have 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. Some computers use a water-cooling system instead of 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.
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 (50 °F) below this. At 45 °C (113 °F) a lifetime of 15 years can be expected.
Motherboards are produced in a variety of sizes and shapes called computer form factor, some of which are specific to individual computer manufacturers.
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.
Other information
Motherboards are generally air cooled with heat sinks mounted on larger chips, such as the Northbridge. Insufficient or improper cooling can cause damage to the internal components of the computer and cause it to crash. Newer motherboards have 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. Some computers use a water-cooling system instead of 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.
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 (50 °F) below this. At 45 °C (113 °F) a lifetime of 15 years can be expected.
Motherboards are produced in a variety of sizes and shapes called computer form factor, some of which are specific to individual computer manufacturers.
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.
Other information
- It is the primary printed circuit board in a computer or other electronic device.
- In a modern desktop computer, the motherboard contains the CPU and memory sockets as well as the chip set, which houses the control circuits for all the peripheral devices. It also has a PCI-Express slot for a high-end display adapter and PCI slots for additional peripherals.
- Laptop motherboards have no expansion slots for more peripherals.