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The Heart Of The Computer Using our human body analogy, the brain of every computer system is the processor, but the heart is the motherboard. Without a heart, no blood can flow and no brain activity can occur. Without a motherboard, no electrical signals can travel and no processing can occur. The motherboard and processor together are the two most important elements of a computer system. The form factors, and CMOS and BIOS settings. Form Factors Since the very first motherboard was produced, standards were used to state how a motherboard was shaped and installed. These are called form factors, and three distinct form factors exist in computers today;
On each standard for form factors, there is a sub-standard called integration. Every motherboard is designed to either be non-integrated or integrated. The difference is whether or not equipment such as video cards and disk controllers are attached to the system. If the video card or disk controller is a part of the motherboard, it is considered an integrated motherboard. Motherboards that require expansion cards for these services are called non-integrated motherboards. The major advantage of having totally non-integrated systems was that if a part failed, only that part had to be removed. Manufacturers quickly realized that producing one board with all these parts included was a significant cost savings, and started producing most of their boards with integrated components. Every motherboard you buy today is integrated in some fashion. IBM, Intel, and Dell use integrated video cards and sound cards, and almost every motherboard produced has a built-in disk controller. Originally, to distinguish themselves from clone systems, manufacturers began making their systems proprietary. Proprietary systems are systems that required the manufacturer's specific parts in order to operate. To this day, most major manufacturers continue to use proprietary motherboards and cases, but have stopped producing systems that can't be expanded with add-in video cards, sound cards, and modems. If you are working on a 386, 486, or early Pentium system from a major manufacturer, make sure you are aware of what parts you can use and what parts you can't before you tell a customer a remedy for a failure. Sometimes a system won't even function with generic RAM installed or non-proprietary expansion boards installed. Standard Components of a Motherboard Every motherboard is a myriad of parts squeezed together to form a whole system. These parts are connected by electrical wiring built into the motherboard itself. Think of a motherboard like a city. The roads are the electric wires connecting each of the buildings, or components. Some of this wiring is surface (roads) and some is built in underground (subways) They all serve to allow traffic to flow between buildings, the same way electrical wiring allows electrical signals to flow between components. The same way a city gets more congested as it gets bigger, a motherboard gets congested as more and more equipment is attached to it. Therefore, there are trade-off's in motherboard technology. As wires can be made smaller, and as signals can be transferred faster, these tradeoffs become of less and less significant. It is important to remember that as technology for processors and video cards has grown, it has grown the technology in other areas of the computer as well. The Microprocessor Without a microprocessor, the motherboard is useless. In most cases the motherboard and processor are almost synonymous, as the motherboard is dependant on the processor type and vice versa. Because of this, great emphasis is put on processor styles and terminology. You must know the processor sockets, Co-processors, Clock speeds, Bus widths, manufacturers, and more. Be familiar with the terms and you will have no problems. Processor
Characteristics
The Form Factor abbreviates above mean;
With the current rise in the AMD (American Micro Devices) processor's popularity, expect more questions about AMD processors. Remember that AMD used a mixture of RISC-based (Reduced Instruction Set Computing) instructions and 3DNow technology (similar to MMX) to speed up their processors to speeds comparable to the Pentium processors. The AMD K7 Athlon processor is the fastest CISC (Complex Instruction Set Computing) chip in mass production, and Intel's Pentium 4 processor is due for release this March. I will update the listings on this lesson as the need arises, but please check the latest technical specifications for the latest-breaking information. One other important note. With each form factor and chip combination, there is another "Chip-set" created. Certain processors work in multiple chipsets, and some had specific chipsets just for that single processor. MMX, 3DNow!, and Coprocessors Processor manufacturers are always looking for ways to speed up their existing chip designs, or patent new technology in their newest designs. In the x086 realm, they did this with coprocessors. A coprocessor up until the 486DX processor was a separate processor on the motherboard that handled larger number-crunching duties. When the 486DX processor was produced, they integrated the numeric or math coprocessor onto the microprocessor, and all processors since have included a "Floating-Point" math coprocessor in the chip design. When Intel decided to release the 586 processor, they had seen the producers such as AMD and Cyrix making duplicates of their chips. Because Intel couldn't patent a number (ie 586), they decided to call it a Pentium processor. (A pentagon is a 5-sided object) This allowed them to patent the Pentium brand name, and stopped other manufacturers from producing chips named similar to Intel's line. This probably won't be on your test, but is an interesting side-note to Intel's naming scheme for processors. MMX, Or Multi-Media Extensions, is a technology Intel added to it's Pentium processor that gave the processor 57 new instructions, SIMD technology (single instruction, multiple data) and 32K of cache. SIMD technology allows one instruction to control several data items, increasing the speed of the processor. In response, AMD created 3DNow! technology, which gave their processors MMX-like instuction sets. Cooling Fans and Thermal Grease With the 8086 processors, heat dissipated off the chip simply through the computer's ability to circulate air. This continued through the 286, 386, and some of the 486 family. Eventually, the heat generated by the chip started overheating the processor, and fans began to appear on processors to cool them down. By the release of the Pentium 100 MHz, all processors were coming with fans installed to cool them down. Currently, there are several methods for cooling processors, and most use a combination of all these techniques. First of all, the circulation systems inside a processor suck cool air across the processor. This makes it vitally important to keep the case of a computer closed, as proper circulation can only be maintained with a closed case. I say this to you with a small fan blowing onto my CPU from beside my open case-all technicians hate having their cases closed. But as far as any computer other then your own is concerned, close the case. The second method is the use of a heat sink/fan combination. They sit on top of the processor with the heat-sink touching the top of the processor. The heat sink absorbs the heat from the processor, and the fan dissipates that heat throughout the computer. Remember that the first computers blew heat away from the processor and that the newer computers suck air in. The last method is the use of thermal grease, or thermal compound. It is normally used between the heat sink and the processor, both to secure the processor to the heat sink and to allow greater absorption by the heat sink. It does this by filling minute spaces in-between the processor and the heat sink that trap air and don't allow the absorption of heat by the heat sink. If you ever doubt the ability of a heat-sink and fan, I will send you a scanned image of my left hand. As a joke, one of my employees once sat a processor in my hand that had been running without a fan for about 20 minutes. I have a scar where the processor burnt my hand. Processors are designed to run in the 65-185 degree Fahrenheit area (The Pentium processor is designed to run at 185, my Athlon 800 runs at about 78 degrees), but shoot over 250 degrees easily without a fan. This can cause unexplained system shutdowns, crashes, and errors, as heat causes the parts of a processor to stop functioning. Most processors have heat sensors that will turn the computer off before damage occurs, so if you have a system that turns off for no reason, check the processor fan. The 4 Buses The electrical signals that travel through the motherboard travel along small wires that interconnect all the components of a motherboard. This network of wires is called a bus, and is split into 4 distinct types and 2 distinct sections. The bus structure is divided into an internal and an external bus. The internal bus is the network that connects all equipment native to the motherboard. Therefore, any part of the bus that connects to components soldered to the motherboard itself are considered on the internal bus. The external bus is any wiring connecting to equipment attached to the motherboard but not native to it. In our human body analogy, the internal bus could be related to the nervous system in the spine, where the external bus would be the nerves running to the extremities. The four different types of bus structures are; Address - The
components on the motherboard pass memory information to each
other over the address bus. Buses are measured in bits, which are the width of the data that can pass through them. It corresponds to the number of wires signals can travel simultaneously. For example, a 32bit data bus has 32 wires that can transmit 32 bits of information at the same time. ©2002 COMPUTER INFO All rights reserved.
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