Introduction to computer systems. Architecture of a computer systems презентация

Lecture 2 Topic: Introduction to computer systems. Architecture of a computer systems.

Plan of Lecture: The development of computer architecture. Von Neumann architecture. Types of computers. The basic components of a computer. The memory chips. Microchips processors and tires. Presentation of data in computer memory.

Technology The technology is moving very quickly 19th century: attempts to build mechanical computers Early 20th century: mechanical counting systems (cash registers, etc.) Mid 20th century: vacuum tubes as switches Since: transistors, integrated circuits

Charles Babbage In the early 1800’s Charles Babbage designed two machines: first the Difference Engine and then the Analytical Engine that were mechanical machines capable of performing calculations. The Difference Engine, most (but not all) of which was built in Babbage’s time, was a special purpose machine (i.e. it could only do particular calculations). The Analytical Engine, which was designed but not built in Babbage’s time, was more ambitious in that it was programmable.

Fast forward a hundred years In the 1940’s the Electronic Numerical Integrator And Computer (ENIAC) was built at the Moore School of the University of Pennsylvania. It was completed in 1946 at the Moore School of the University of Pennsylvania. The two driving forces behind it were John W. Mauchly and J. Presper Eckert. There were other computers built during WWII notably the one developed at Bletchley Park, UK to aid in their code breaking mission.

ENIAC The ENIAC consisted of 17,480 vacuum tubes operating at 100,000 pulses per second. Vacuum tubes play the same role that transistors do in modern computers (one can use them to “realize” logic gates (вентили)) The switch from vacuum tubes to transistors marked a dramatic shift in computer size and speed. The Pentium 4 processor introduced in 2000 had 42,000,000 transistors. The Itanium 2 in 2004 had 592,000,000 transistors. The more recent Core i7 processor has a transistor count is 731 Million.

Vacuum tube

Von Neumann Architecture John von Neumann was a consultant to the ENIAC project. The team discussed changing the way computers were programmed. Von Neumann publicized these ideas. The instructions could be converted into numbers and placed in memory along with the data. This is known as the stored program concept. The combination of the basic units (ALU, control, memory, input and output) and the stored program concept give one the “von Neumann architecture.”

Types of computers: personal computer: a small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data. workstation: a powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

Types of computers: minicomputer: a multi-user computer capable of supporting from 10 to hundreds of users at the same time. mainframe: a powerful multi-user computer capable of supporting many hundreds or thousands of users at the same time. supercomputer: an extremely fast computer that can perform hundreds of millions of instructions per second.

Types of Computers

Servers Computers connected in a network environment. Manage network resources Holds and delivers an organization’s web pages Stores and retrieves tasks for all of an organization’s files A printer server handles all print requests.

First computers, introduced in 1950s First computers, introduced in 1950s Used by large businesses Typically supported hundreds or thousands of users Very expensive Used for very large processing tasks

Supercomputers High capacity (высокая емкость) Used by very large organizations Tracking space Tracking weather

Typically supported hundreds of users Typically supported hundreds of users No longer a product line Smaller and less expensive than mainframes The real difference is relative in terms of price, power, marketing. Known as midrange computers

Computer Systems

Motherboard A motherboard is the central printed circuit board (PCB) in many modern computers and holds many of the crucial components of the system, while providing connectors for other peripherals. The motherboard can be easily compared to the human body’s nervous system. The wires (nerves) on it transfer data between all of the other components.

Main Components of a Computer System Processor (CPU) Runs program instructions Main Memory Storage for running programs and current data Secondary Storage Long-term program & data storage (hard disk, CD, etc) Input Devices Communication from the user to the computer(e.g. keyboard, mouse) Output Devices Communication from the computer to the user (e.g. monitor, printer, speakers)

The Processor

Component Interaction

Central Processing Unit (CPU)

Registers

CHARACTERISTICS of Processor

Memory Computer Memory - millions/billions of on/off charges  Divided into: Bits 0 or 1 Bytes Groups of 8 bits A byte is the smallest unit of storage. (Can hold one text character) Words Groups of bits/bytes (8, 16, 32, 64-bits)

Memory Storage is usually too large to be expressed in bytes or words. Instead we use: Kilobyte (KB) = 1024 bytes (210 bytes) Megabyte (MB) = 1024 x 1024 bytes or one million bytes (220 bytes) Gigabyte (GB) = 1024 x 1024 x 1024 bytes or one trillion bytes (230 bytes) Terabyte (TB) = 1024 x 1024 x 1024 x 1024 bytes one quadrillion bytes (240 bytes)

Main Memory

Main Memory Characteristics Very closely connected to the CPU. Contents are quickly and easily changed. Holds the programs and data that the processor is actively working with. Interacts with the processor millions of times per second. Nothing permanent is kept in main memory.

Program Instructions

Instructions An instruction is a sequence of bits. A simple instruction format may consist of an operation code (op code) and an address or operands.

Instructions The operation code specifies the operation the computer is to carry out (add, compare, etc) The operand/address area can store an operand or an address An operand is a specific value or a register number An address allows the instruction to refer to a location in main memory The CPU runs each instruction in the program, starting with instruction 0, using the fetch-decode-execute (выборки-декодирования-выполнение ) cycle.

Fetch-Decode-Execute Diagram

The main device of PC

System bus The processor sets the address bus memory address, which wants to read; (Процессор устанавливает на шине адреса адрес ячейки памяти, которую хочет прочитать); On the control bus puts the processor ready signal and the read signal; (На шине управления процессор выставляет сигнал готовности и сигнал чтения); Noticing the ready signal, check all devices, whether or not on the bus addresses of their address; (Заметив сигнал готовности, все устройства проверяют, не стоит ли на шине адреса их адрес); RAM, noting that exposed her address, reads the control signal; Memory read address; (Оперативная память, заметив, что выставлен ее адрес, считывает управляющий сигнал. Память читает адрес); Memory Bus exposes the requested information data; (Память выставляет на шине данных требуемую информацию); The memory puts the control ready signal bus;(Память выставляет на шине управления сигнал готовности); A processor reads data from the data bus; (Процессор читает данные с шины данных).

The internal memory of the computer

Cache Memory

Controllers Decodes the signal received from processor (Декодирует сигнал, поступающий от процессора) Sends the processed signal to the performance of its device (Посылает обработанный сигнал для выполнения его устройством) The resulting signal is converted into a binary form of user-friendly (Полученный двоичный сигнал преобразует в вид понятный пользователю) Are inserted into the slots (slots) on the motherboard, and to their ports connect additional devices (Вставляются в разъемы (слоты) на материнской плате, а к их портам подключаются дополнительные устройства)

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