UNIT-1 Mother Board: Introduction To MotherBoard: The shape and layout of a motherboard is called the form factor. The form factor affects where individual components go and the shape of the computer's case. There are several specific form factors that most PC motherboards use so that they can all fit in standard cases. The form factor is just one of the many standards that apply to motherboards. Some of the other standards include: The socket for the microprocessor determines what kind of Central Processing Unit (CPU) the motherboard uses. 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. The Basic Input/Output System (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. 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: Peripheral Component Interconnect (PCI)- connections for video, sound and video capture cards, as well as network cards Accelerated Graphics Port (AGP) - dedicated port for video cards. Integrated Drive Electronics (IDE) - interfaces for the hard drives Universal Serial Bus or FireWire - external peripherals Memory slots A motherboard is the heart of a computer. It is the main printed circuit board present in the computers which holds the main electronic components of the system like the central processing unit and memory and also provides the connectors for other important peripherals. A motherboard is a large system in itself which contains a number of subsystems like the processor and other components. The basic function for which a motherboard is used in a computer is that it holds the important electronic components of the system including the memory and central processing unit and helps in establishing some sort of bridged connection between other internal components of the system. Motherboard affects the speed of the computer system. A good motherboard, which will be properly compatible with the components of a computer system, will enhance the speed of the computer, while a motherboard which is not compatible with the components of a computer system will negatively affect the speed of the system. There are different types of motherboard which are available. AT Motherboard An AT motherboard is a motherboard which has dimensions of the order of some hundred millimeters, big enough to be unable to fit in mini desktops. The dimensions of this motherboard make it difficult for the new drives to get installed. The concept of six pin plugs and sockets is used so as to work as the power connectors for this type of motherboards. It is mainly produced in the mid 80’s and this motherboard lasted a good span from the Pentium p5 to the times when Pentium 2 had been started to be used. ATX Motherboard Advanced technology extended, or popularly known as the ATX, are the motherboards which were produced by the Intel in mid 90’s as an improvement from the previously working motherboards such as AT. This type of motherboards differ from their AT counterparts in the way that these motherboards allow the interchangeability of the connected parts. Moreover the dimensions of this motherboard are smaller than the AT motherboards and thus proper place for the drive bays is also allowed. Some good changes were also made to the connector system of the board. The AT motherboards had a keyboard connector and on the back plates extra slots were provided for various add- ons. LPX Motherboard The low profile extension motherboards, better known as LPX motherboards, were created after the AT boards in the 90’s. The major difference between these and previous boards is that the input and output ports in these boards are present at the back of the system. This concept proved to be beneficial and was also adopted by the AT boards in their newer versions. The use of a riser card was also made for the placement of some more slots. But these riser cards also posed a problem that the air flow was not proper. Also, some low quality LPX boards didn’t even have real AGP slot and simply connected to the PCI bus. All these unfavored aspects led to the extinction of this motherboard system and was succeeded by the NLX. NLX motherboard (New Low-Profile EXtended motherboard) A low-profile PC motherboard from Intel for slimline cases, introduced in 1987. Unlike boards for desktop and tower cases that hold the expansion cards perpendicular to the board, cards plug into a riser card on the NLX and are parallel with the board. BTX Motherboard BTX stands for Balanced Technology extended. BTX was developed to reduce or avoid some of the issues that came up while using latest technologies. Newer technologies often demand more power and they also release more heat when implemented on motherboards in accordance with the circa-1996 ATX specification. The ATX standard and the BTX standard, both were proposed by Intel. The first company to use, or to be precise, implement BTX was Gateway Inc, followed by Dell and MPC. Apple’s MacPro uses only some of the elements of the BTX design system but it is not BTX compliant. This type of motherboard has some improvements over previous technologies: Low-profile – With the larger demand for ever-smaller systems, a redesigned backplane that shaves inches off the height requirements is a benefit to system integrators and enterprises which use rack mounts or blade servers. Thermal design – The BTX design provides a straighter path of airflow with lesser difficulties, which results in better overall cooling capabilities. Instead of a dedicated cooling fan, a large 12 cm case-fan is mounted, that draws its air directly from outside the computer and then cools the CPU through an air duct. Another feature of BTX is the vertical mounting of the motherboard on the left-hand side. This kind of feature results in the graphics card heat sink or fan facing upwards, rather than in the direction of the adjacent expansion card. Structural design – The BTX standard specifies distinct locations for hardware mounting points and hence reduces latency between key components. It also reduces the physical strain imposed on the motherboard by heat sinks, capacitors and other components which are dealing with electrical and thermal regulation. Pico BTX Motherboard Pico BTX is a motherboard form factor that is meant to manufacture even smaller size BTX standard. This is smaller than many current “micro” sized motherboards; hence the name “Pico” has been used. These motherboards share a common top half with the other sizes in the BTX line, but they support only one or two expansion slots, designed for half-height or riser-card applications. Mini ITX Motherboard Mini-ITX is a 17 × 17 cm (6.7 × 6.7 in) low-power motherboard form factor. It was designed by VIA Technologies in year 2001. These are largely used in small form factor (SFF) computer systems. Mini-ITX boards can also be cooled easily because of their low power consumption architecture. The four mounting holes in a Mini-ITX board line up with the four holes in ATX specification motherboards, and the locations of the back plate and expansion slot are the same. Although, one of the holes used was optional in earlier versions of the ATX. Hence, Mini-ITX boards can be used in places which are designed for ATX, micro-ATX and other ATX variants if required. Motherboard Basics A computer has many components, each with their own roles and functions. The role of the motherboard is to allow all these components to communicate with each other. Considering the fact that all the other components are installed on the motherboard or connected to it, it is safe to say that the motherboard is the central piece of a PC, the component that brings it all together. Processor Socket The processor socket is the central piece of a motherboard, usually being located near the center of the motherboard. It’s also the central piece because it holds the processor – the brain of your computer. Power Connectors No computer component can operate without power, and a motherboard is no exception. The power connector, commonly a 20 or 24-pin connector, can be situated either near the right edge of the motherboard, or somewhere close to the processor socket on older motherboards. This is where the power supply’s main connector gets attached, providing power to the motherboard and all the other components. Newer motherboards have an additional 4-pin or 8-pin connector near the processor, used to supply additional power directly to the processor. Memory Slots Located in the upper-right part of the motherboard, the memory slots are used to house the computer’s memory modules. The number of slots can vary, depending on motherboard, from 2, in low-end motherboards, all the way up to 8 memory slots, on high-end and gaming motherboards. It is important to pay close attention to the type of memory a motherboard supports, in order to buy the appropriate memory modules. Newer motherboards support DDR3 memory, the current industry standard memory architecture, but motherboards with DDR2 memory slots and even DDR1 memory slots are still present on the market. An interesting aspect is that there are some older motherboard models that supported different types of memory, and usually come with two DDR1 memory slots and 2 DDR2 memory slots, or two DDR2 slots and two DDR3 slots.