Motherboard And Its component What is motherboard:- The main circuit board of micro computer. The motherboard contain Bios cpu Memory mass storage Interface. USB,SATA,Parallel ports expansion slot and all control required to control standard peripheral devices such as the display screen keyboard and disk drive. Mother Board Form Factor The shape and layout of motherboard are called the form factor.i.e physical dimension size of motherboard

Component And Image of MotherBoard

Types of Motherboard Non Integrated Motherboard:- Old Motherboard have assemblies such as I/O port connectors hard drive connector Joysticks. This motherboard is relatively cheap to produce but because of cost of manufacturing cost increases. Any thing go wrong we can repair the problem by replacing the card with minimum cost

Types of Motherboard Integrated Motherboard:- All in one Motherboard. All component are directly connected to motherboard. Less material is involved, less installation and testing can be done at same time. More expensive to repair .

Types of Form Factor PC/XT: First official form factor originated with first desktop PC with IBM PC. Baby AT: was introduced 1993-1997.CPU socket is placed so that interfere with bus card. AT :called Full AT form factor. It was oldest biggest form factor.

Conti…..

ATX Motherboard Parts

ATX Form Factor Created in 1995 About same size as Baby AT Had many ports accessible from rear of PC including mini-DIN RAM was closer to Northbridge and CPU for better performance Uses the soft power feature to turn PC on and off through software

ATX Form Factor

Mini ATX

THE CPU

Motherboard And Its component

CONCEPT OF BUS The motherboard is like a big city with many streets and highways that connect all of the buildings together. Instead of streets and highways, the motherboard uses tiny electrical paths to connect each component of the computer together.

Bus conti…… A bus is simply a circuit that connects one part of the motherboard to another. The more data a bus can handle at one time, the faster it allows information to travel. The speed of the bus, measured in megahertz (MHz), refers to how much data can move across the bus simultaneously.

Processor Modes REAL MODE The original IBM PC could only address 1 MB of system memory, and the original versions of DOS created to work on it were designed with this in mind. DOS is by its nature a single-tasking operating system, meaning it can only handle one program running at a time. The decisions made in these early days have carried forward until now, and in each new processor, care had to be taken to be able to put the processor in a mode that would be compatible with the original Intel 8088 chip. This is called real mode. When a processor is running in real mode, it acts like an "8088 on steroids". What this means is that it has the advantage of speed, but it otherwise accesses memory with the same restrictions of the original 8088: a limit of 1 MB of addressable RAM, and slow memory access that doesn't take advantage of the full 32-bit processing of modern CPUs. All processors have this real mode available, and in fact the computer normally starts up in real mode.Real mode is of course used by DOS and "standard" DOS applications. In fact, today there are relatively few simple DOS programs that just use the standard 640K that DOS makes available. Even within DOS now there are special programs available that will "extend" DOS to allow access to extended memory (over 1 MB) and faster 32-bit access. These are sometimes called DOS extenders. The protocol that describes how to make DOS work in protected mode is called DPMI (DOS protected mode interface). DOS extenders are used by most DOS games (since the standard DOS 640 KB limit has gone from inflexible to downright laughable in recent years as games have become very large).

Protected Mode: Starting with the 80286 chip in the IBM AT, a new processor mode was introduced called protected mode. This is a much more powerful mode of operation than real mode, and is used in all modern multitasking operating systems. The advantages of protected mode (compared to real mode) are: Full access to all of the system's memory. There is no 1 MB limit in protected mode. Ability to multitask, meaning having the operating system manage the execution of multiple programs simultaneously. Support for virtual memory, which allows the system to use the hard disk to emulate additional system memory when needed. Faster (32-bit) access to memory, and faster 32-bit drivers to do I/O transfers.

Conti…… The name of this mode comes from its primary use, which is by multitasking operating systems. Each program that is running has its own assigned memory locations, which are protected from conflict with other programs. If a program tries to use a memory address that it isn't allowed to, a "protection fault" is generated. If you've ever used Windows 3.x, you know exactly what I am talking about. : Although introduced with the 286, the operating system world back in the early 80s was stuck squarely in DOS. The use of protected mode didn't become popular until the rise in dominance of the Microsoft Windows operating system. Protected mode is now currently the way that most people use their PCs. All of the major operating systems today use protected mode, including Windows 3.x, Window 9x, Windows NT, OS/2 and Linux. Even DOS, which normally runs in real mode, can access protected mode using DPMI (DOS protected mode interface), which is often used by DOS games to break the 640 KB DOS conventional memory barrier. All processors from the 286 on can use protected mode. 386 and later processors can switch on the fly from real to protected mode and vice-versa; the 286 can only switch from real to protected mode once (switching back requires a reboot). Protected mode is also sometimes called 386 Enhanced Mode, since it became mainstream with that family of processors.

CARD IMAGE ON MOTHERBOARD

Northbridge Southbridge Super I/O chip Chipset Chips Helps the CPU work with RAM (on Intel-based systems) Communicates with video on newer AMD systems Southbridge Handles expansion devices and mass storage drives Sits between expansion slots and EIDE and FDD controllers Also called the I/O Controller Hub (ICH5) or peripheral bus controller Super I/O chip Provides legacy support

Intel Chipsets Chipset North-bridge South-bridge CPU RAM Intel 975X Express 8295X MCH 82801 GB ICH, 82801 GR ICH, 82801 GDH ICH LGA 775 Core 2 Extreme, Core 2 Due, Pentium 4, Pentium 4 with HT, Pentium D Dual-channel DDR2 up to 8 GB Intel P965 Express 82P965 GMCH P965 ICH8 All LGA775 Intel 9100GL Express 82910G GMCH ICH6 or ICH6R Pentium 4 with HT, Celeron D DDR up to 2 GB

NVIDIA Chipsets Chipset North-bridge South-bridge CPU RAM NVIDIA nForce-4 nForce4 1 Athlon 64, Athlon 64 FX, Sempron 2 NVIDIA SL1 Intel nForce 570 SL1 Intel LGA 775, Core 2 Extreme, Core 2 Duo, Pentium D, Pentium 4, Celeron D Dual-channel DDR2 NVIDIA nForce 590 SLI AMD nForce 590 SLI Atlon 64, Athlon 64 FX, Athlon 64 X2 NVIDIA doesn’t make a Northbridge/Southbridge distinction Athlon has MCC built into CPU so RAM capabilities are determined by CPU, not chipset

VIA Chipsets Chipset North-bridge South-bridge CPU RAM VIA K8 Series K8T900 VT8251 Opteron, Athlon 64, Athlon FX, Sempron VIA P4 Series PT890 VT8237A Pentium 4, Celeron SDRAM with ECC, DDR, DDR2 up to 4 GB Athlon has MCC built into CPU so RAM capabilities are determined by CPU, not chipset

Motherboard Bus Expansion slots allow adapters to be installed into the motherboard to add capabilities to the PC. Users must be able to identify expansion slots and distinguish between the adapters that use them. The user must be able to install the proper adapter in the correct expansion slot and configure both correctly.

ISA (Industry Standard Architecture) – ISA (Industry Standard Architecture) – The oldest expansion slot that is configured in 8-Bit and 16-Bit slots. Also referred to as the AT bus. Operates at 8MHz, although some manufacturers reliably achieve a throughput of 10 MHz.

EISA (Enhanced Industry Standard Architecture) 32-bit expansion slot that is the same length as an ISA slot and twice as deep. A non-proprietary architecture developed by a group of nine vendors in response to IBM’s proprietary Micro Channel Architecture. A 32-bit, 10MHz standard that also allows ISA adapters to operate in the expansion slots. This standard was never as successful as the designers hoped.

PCI (Peripheral Component Interconnect) – The most popular expansion slot that is configured in both 32-bit, 33MHz and 64-bit, at 33MHz and 66MHz. A new standard is the PCI-X which can operate at 66MHz, 133MHz, 266MHz, and 533MHz. PCI-X 1066MHz is being developed. PCI adapters are configured with software and the standard supports bus-mastering, which allows an adapter to take over the external bus from the CPU and execute operations with another bus-mastering adapter without going through the processor.

PCI-X

Accelerated Graphics Card AGP (Accelerated Graphics Port) – 32-bit bus interface for graphics adapters developed from the PCI bus. It speeds up 3-D graphics, 3-D acceleration, and full-motion playback. Allows the video adapter to directly access RAM on the motherboard when needed. The video subsystem is isolated from the rest of the computer. In order to implement AGP, the motherboard must have an AGP expansion slot, the chipset must support AGP, and an operating system that supports AGP must be installed. Some motherboards will allow changing the amount of memory AGP can use. The amount normally used is 64MB, configured through BIOS settings, and referred to as the AGP Aperture.

Logical Memory Organization

Memory Image

Logical Memory Organization

Cache Memory

CACHE HITS / MISSES Cache Hit: a request to read from memory, which can satisfy from the cache without using the main memory. Cache Miss: A request to read from memory, which cannot be satisfied from the cache, for which the main memory has to be consulted.

BIOS and CMOS

Motherboard Selection Criteria Processor Processor socket Motherboard speed Cache memory Form Factor PnP Power Management Bios CMOS