Architecture Components
§ Hardware
Ø Processes data by executing instructions
Ø Provides input and output
§ Software
Ø Instructions executed by the system
§ Data
Ø Fundamental representation of facts and observations
§ Communications
Ø Sharing data and processing among different systems
Fundamentals of the computer architecture was laid by John von Neumann. The combination of these principles gave rise to the classical (von Neumann) architecture computers.
Von Neumann did not only put forward the basic principles of computer logic device, but also suggested that the structure shown in Fig.
Von Neumann model describes a design architecture for an electronic digital computer with subdivisions of a processing unit consisting of an arithmetic logic unit and processor registers, a control unit containing an instruction register and program counter, a memory to store both data and instructions, external mass storage, and input and output mechanisms.
An arithmetic logic unit - performs logical and arithmetic operations required to process the information stored in the memory.
The control unit - provides management and control of all devices in the computer.
For input and output are used input and output devices.
An arithmetic logic unit and control unit in the form of modern computer processor computer. The processor, which consists of one or more large-scale integrated circuits called a microprocessor or a microprocessor kit.
The PC is a microcomputer, according to the traditional division of computers based on size.
At the highest level, a computer consists of a processor, memory, and I/O components, with one or more modules of each type. These components are interconnected in some fashion to achieve the main function of the computer. So, the computer has four main structural elements:
A motherboard (sometimes alternatively known as the mainboard, system board) is a printed circuit board (PCB) found in many modern computers which holds many of the crucial components of the system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals.
In computer architecture, a bus (шина) is a subsystem that transfers data between components inside a computer, or between computers.
Processor - the functional part of a PC that carries out the instructions of a computer program by performing the basic arithmetical, logical, and input/output operations of the system. The processor is a transducer of information from memory and peripheral devices.
Процессор – функциональная часть ПК, выполняющая основные операции по обработке данных и управлению работой других блоков. Процессор является преобразователем информации, поступающей из памяти и внешних устройств.
There are a few different manufacturers of CPUs, however, the clear leaders in the marketplace are Intel and AMD
The clock rate is the speed at which a microprocessor executes instructions. Every computer contains an internal clock that regulates the rate at which instructions are executed and synchronizes all the various computer components. The CPU requires a fixed number of clock ticks (or clock cycles) to execute each instruction. The faster the clock, the more instructions the CPU can execute per second.
The width of the data bus (remember the 32 bit, 64 bit). Its the number of bits that a processor is tagged with refers to how many bits of data and memory address size the data bus can accommodate at one go. The more bits of data and memory address a processor can process at one go, the faster it is considered!
The number of cores present on the processor. More processors enable the computer to perform multiple tasks at the same time, without having to wait for the completion of one task before starting the next. On these lines, we have single core processors, dual core processors, quadruple core processors, and so on.
Выпускаются сейчас: Intel Core 2 - восьмое выпущенное корпорацией Intel поколение микропроцессоров архитектуры x86, основанное на совершенно новой процессорной архитектуре, которая называется Intel Core.
делятся на модели Solo (одноядерные), Duo (двухъядерные – кэш память 2го уровня до 6Мб, системная шина с частотой до 1333МГц), Quad (четырёхъядерные – кэш память 2го уровня до 12Мб, общая частота до 2,66ГГц) и Extreme (четырёхъядерные с высочайшей скоростью и разблокированным множителем – кэш память 2го уровня до 12Мб, общая частота до 3ГГц). В архитектуре Core 2 ставка делается не на повышение тактовой частоты, а на улучшение других параметров процессоров, таких как кэш, эффективность и количество ядер.
Семейство AMD64:
Процессор AMD Opteron – сервера и рабочие станции (ядроBarcelona 4-ядерные)
Процессор AMD Athlon 64 – настольные станции и ноутбуки (ядра Toledo, Windsor - 2-ядерные)
Мобильная технология AMD Turion 64 – ноутбуки (ядро Taylor 2-ядерные)
Random access memory (RAM) is a form of computer data storage. A random access device allows stored data to be accessed in any order in very nearly the same amount of time for any storage location or size of memory device. Each location contains a bit pattern that can be interpreted as either an instruction or data. This memory is typically volatile – when the computer is shut down, the contents of its contents are lost.
Read-only memory (ROM) is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware (software that is very closely tied to specific hardware, and unlikely to need frequent updates).
In IBM PC compatible computers, the Basic Input Output System (BIOS), also known as the System BIOS, is a de facto standard defining a firmware interface.
A hard disk drive (HDD) is a device for storing and retrieving digital information, primarily computer data. It consists of one or more rigid (hence "hard") rapidly rotating discs (platters) coated with magnetic material, and with magnetic heads arranged to write data to the surfaces and read it from them.
HDD is the dominant device for secondary storage of data in general purpose computers because of advances which have resulted in increased recording capacity (GB or TB), reliability, and speed, as well as decreased cost, allowing them to keep pace with ever more demanding requirements for secondary storage.
Some other examples of secondary storage technologies are: flash memory (e.g. USB flash drives), floppy disks, rotating optical storage devices, such as CD and DVD drives.
The secondary storage is often formatted according to a file system format, which provides the abstraction necessary to organize data into files and directories, providing also additional information (called metadata) describing the owner of a certain file, the access time, the access permissions, and other information.
For any particular implementation of any storage technology, the characteristics worth measuring are capacity and performance.
Controller is a chip, an expansion card, or a stand-alone device that interfaces with a peripheral device. This may be a link between two parts of a computer (for example a memory controller that manages access to memory for the computer) or a controller on an external device that manages the operation of (and connection with) that device.
For example, a network interface controller (also known as a network interface card, network adapter, LAN adapter) is a computer hardware component that connects a computer to a computer network.
A printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a USB cable to a computer which serves as a document source.
In addition, a few modern printers can directly interface to electronic media such as memory cards, or to image capture devices such as digital cameras and scanners; some printers are combined with scanners or fax machines in a single unit, and can function as photocopiers. Printers that include non-printing features are sometimes called multifunction printers (MFP), multi-function devices (MFD), or all-in-one (AIO) printers. Most MFPs include printing, scanning, and copying among their many features.
Printers are routinely classified by the printer technology they employ: support of different levels of image or text quality, print speed, cost, noise, types of physical media etc.
The following printing technologies are routinely found in modern printers:
A laser printer rapidly produces high quality text and graphics. As with digital photocopiers and multifunction printers (MFPs), laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor.
Inkjet printers operate by propelling variably-sized droplets of liquid ink onto almost any sized page. They are the most common type of computer printer used by consumers. Today's photo-quality ink jet printers can typically print with a resolution of 1200 to 4800 dots per inch. They will give acceptable quality photo prints of images with 140-200 pixels per inch (PPI) resolution, and high quality prints of images with 200-300 ppi resolution.
Dot matrix printer is impact printer that use a matrix of small pins to create precise dots that prints by impact, striking an ink-soaked cloth ribbon against the paper, much like the print mechanism on a typewriter. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies.
The advantage of dot-matrix over other impact printers is that they can produce graphical images in addition to text; however the text is generally of poorer quality than impact printers that use letterforms.
Advantages
Dot matrix printers, like any impact printer, can print on multi-part stationery or make carbon-copies. Impact printers have one of the lowest printing costs per page. As the ink is running out, the printout gradually fades rather than suddenly stopping partway through a job. They are able to use continuous paper rather than requiring individual sheets, making them useful for data logging. They are good, reliable workhorses ideal for use in situations where printed content is more important than quality. The ink ribbon also does not easily dry out, including both the ribbon stored in the casing as well as the portion that is stretched in front of the print head; this unique property allows the dot-matrix printer to be used in environments where printer duty can be rare, for instance, as with a Fire Alarm Control Panel's output.
Disadvantages
Impact printers create noise when the pins or typeface strike the ribbon to the paper. Sound dampening enclosures may have to be used in quiet environments. They can only print lower-resolution graphics, with limited color performance, limited quality, and lower speeds compared to non-impact printers. While they support fanfold paper with tractor holes well, single-sheet paper may have to be wound in and aligned by hand, which is relatively time-consuming, or a sheet feeder may be utilized which can have a lower paper feed reliability. When printing labels on release paper, they are prone to paper jams when a print wire snags the leading edge of the label while printing at its very edge. For text-only labels (e.g., mailing labels), a daisy wheel printer or band printer may offer better print quality and a lesser chance of damaging the paper.
An image scanner - is a device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image. Common examples found in offices are variations of the desktop (or flatbed) scanner where the document is placed on a glass window for scanning. Hand-held scanners, where the device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical.
The main features of a scanner are:
1. The type of feeder (flatbed, paged, projection, drum).
2. Interface - LPT, USB.
3. Software compatibility - One key feature of a scanner is the type of software it requires to operate and whether or not that it is compatible with your particular computer. It is important to identify if the specific drivers needed to make the scanner work with your computer are included with the scanner itself. Without them, the scanner will be all but useless to you.
4. Resolution/Color Depth - the color depth of a particular scanner is important which means the quality of scanned images, measured usually in DPI (dots per inch) the more high dpi number a scanner holds, a more perfect image quality you get.
5. Scan speed - measured in pages per minute.
6. Size of scanned image - traditional flatbed scanners can handle up to legal size paper which is 8.5 x 14″. If one needs to scan images larger than may need to upgrade to a large format flatbed scanner or even a larger sheet-fed scanner.
7. Warranty/Service - As is often the case with electronic equipment, problems can and do occur. This makes one of the key features of any scanner the warranty or service plan that it includes.
8. Price - While it may not be obvious to some, price can often be one of the most important features of any scanner.