3.5. PC COMPUTER SYSTEM

PC is an acronym for 'Personal Computer', a title company IBM (International Business Machines) has awarded its first desktop computer that was used for the user's personal use. The first operating system that is used on the computer, it was one user and one task (DOS), so computer is designed for one person. PC had (and still has) a strictly defined size and arrangement of casing and size slots for inserting additional cards with a variety of purposes, no matter what the shape of the grooves and method of data transmission changed with time. Stated, with free use of its publicly available specification, allow making it compatible computers from other manufacturers (PC compatible), and thus decrease prices and excellent distribution.

Apart from the slot for the microprocessor, BIOS and slots for additional devices, the first motherboards there was almost nothing else, which allowed independent producers to produce various hardware, either consumer or very specialized and meant for, as well as different programming support either that comes to software and meant for general (such as Lotus 1-2-3) or specialized software for one area (such as AutoCAD). No matter what the PC during its development underwent a series of changes, the maximum length, width and height of built cards are still the standard, and the amount of software written for all operating systems on the PC used or still use them is enormous. Such an essential factor in the popularity and continual development PC. So, PC or PC compatible computer is a computer for personal use, which in its conception has the term standardization essential peculiarities of the dimensions onwards. Computers 'Macintosh' company Apple, is also a personal computer, but the manufacturer does not allow the freedom and creativity that has enabled PC manufacturer and, indeed tightly controlled and sealed product, with little opportunity for changes and additions.

Some circuits PC systems were seen many changes over time as technology has progressed making its components. Sometimes these changes in different parts of the system were of such a nature that they are basically changing the way they function. But a very large spread of PC technology and the agreements enabled PC equipment manufacturers are rapidly implement changes (a few months), which would then represent a new standard in the development of PC and therefore can also find a variety of versions PC components and organization of your PC.

Despite the rapid and effective penetration of PCs on the market, the essence of a PC has not substantially changed, and with his knowledge of the functional units described in the following pages apply to both existing systems and future generations of PCs.

Figure* 3.5.1 Usual appearance of the PC system. ( + / - )

System PC (Personal Computer) is currently the most spread version of the so-called support. AT (Advanced Technology) architecture based on the IBM PC platform with Intel's 80x86 series microprocessors and their mathematical subsystem series 80x87. The first PC had an Intel processor 8086, which was eventually refined and developed 80286 processors and associated him 80287 math coprocessor (FPU - Floating Point Unit), 80386 and accompanying his math coprocessor 80387 and 80486 with built-in math coprocessor, and then follow Pentium MMX with tags, PRO, II, III, and 4, of course complemented with math coprocessor. But have been developed and more powerful models such Xeon® Pentium HT, Pentium® D, and their poorer and less expensive version called Celeron. Core™ 2, second, third, fourth and fifth generation of Core™ microprocessors (Core™ i3 to Core™ i7), and their corresponding server microprocessors series XEON the newer versions of the microprocessor manufacturer. According to the original processor are all backward compatible, and all belong to the x86 family.

Pentium 4 is the first serious revision the x86 architecture. It turned out that x86 compatibility prevents increased efficiency processor architectures and solutions are introduced as NetBurst, then HT (Hyper-Threading), and most recently multicore processors (Dual Core, Quad Core) in order to maximize the effect of the speed of execution of instructions, or allow the simultaneous execution of several of them through multiple branches. It is expected that the further technological development of microprocessors are based on a concept of multiple kernel with integrated graphics capabilities.

Many companies have tried to compete with Intel in its products. The most successful is the company AMD (Advance Micro Devices), which is the rate followed Intel products, Intel and cloned each step in the process of making processor series to the 80486th K5 processor was their first independently created x86 compatible processor. Significant shift K6 processor that supports Intel's MMX technology, including fifty new instructions designed to reinforce and accelerate program support for multimedia. But the real 'war' has caused the release of the AMD Athlon (developed under the name K7). Athlon does not execute x86 instructions directly but are decomposed into smaller operations whose execution can proceed efficiently in parallel. Therefore it is more effective. Athlon's first x86 processor with consistently applied techniques in the execution of FP instructions that are not designed at Intel.

3.5.1. Organization and Structure

So the PC where it all happens on the principles of the x86 architecture, and a block diagram of one of the original computers based on this architecture shows the next image. The basis of a computer's motherboard (main board, system), is the largest of all the printed circuit boards in a computer, which integrates the entire computer operation. It is presented as multilayer printed boards in four or more layers in which the conductors are installed to connect the elements on the plate.

Contains several functional units, namely:

             1. Processor and associated components
                (clock generator, coprocessor ...)
             2. ROM in which the BIOS
             3. RAM - working memory with R/W property
                (reading/writing)
             4. I/O input/output devices and channels
             5. Controls system

The processor and its associated elements are worried how to manage data in exercise management and control over the handling of the data, the ROM is responsible for defining the initial and basic parameters of the system, the RAM memory on current usage, and I / O circuits (cards) take care of upgrading system with regard to the display on the monitor, the lasting memory storage systems, modem and network communication, routing the printer and the like. I / O channels (port) are part of the system to connect to devices through which the traffic between the device and the microprocessor and memory, each with its own gateway address at which recognizes (as name) and registered in the first few kB memory folder.

Scheme of the device connection PC system is shown in Figure 3.5.2.

Figure 3.5.2 Block diagram of PC motherboard.

Integrated circuits system, I / O communication through the system and form a so-called DMA. 'Chipset' - a set of chips, today almost all integrated in a common casing. Well-known manufacturers of chipsets for PC are Intel, NVIDIA, AMD, OPTI, VIA and SIS. In the picture you can not see the disk system, since it essentially belongs to the extension through the I / O ports, or via the built-specific interfaces such SATA embedded on the motherboard along with the associated controller, composed chipsets or separately. An integral part of modern motherboards increasingly the music and the power subsystem, and sometimes graphics subsystem, and circuits and interfaces for USB and IEEE 1394 communication. No these extensions are only a supplement presents a block diagram. During technological development mode signaling and communication between the individual components shown in the block diagram is constantly changing, but this functionality Schematic interpretation does not change.

Stroke is something that manufacturers gladly appear in all possible ways. Since the clock generator (meter) multiplying and dividing the working frequency is obtained operating frequency core processor, its cache memory, working memory, buses, and other devices. Therefore regarding the alignment of the individual components used for this purpose designed controllers within the chipsets or elsewhere. Radar systems have been developed in almost independent discipline, and they all have their own specific parameters that appear in very different ways. Therefore, this should independently analyzed, a theme later Chapter.