Introduction to Computers PDF

Introduction to Computers Dr.Ebtsam Eldesoky 1  Introduction to Computers What Is A Computer ? Computer is an electronic device: accepts input processes data stores data produces output (all according to a series of stored instructio...

Introduction to Computers Dr.Ebtsam Eldesoky 1  Introduction to Computers What Is A Computer ? Computer is an electronic device: accepts input processes data stores data produces output (all according to a series of stored instructions) USER is anyone who communicates with a computer or utilizes the information. 2  Computer’s applications Computers are used in various fields such as: Engineering Design Education Health care Business Chemical Analysis Weather Forecast Space Research Medical Diagnosis 4  Generations of computers First Generation Computers: The period of first generation was from 1946-1959. The computers used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit). Unreliable Supported machine language only Very costly Generated a lot of heat Slow input and output devices Huge size Non-portable 5  2nd generation Second Generation Computers: The period of second generation was from 1959-1965. In this generation, transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster. Assembly language and high-level programming languages like FORTRAN, COBOL were used. 6  3rd generation Third Generation Computers: The period of third generation was from 1965-1971. The computers of third generation used Integrated Circuits (ICs) in place of transistors. A single IC has many transistors, resistors, and capacitors along with the associated circuitry. IC used Smaller size Faster Lesser maintenance Costly 7  4th generation Fourth Generation Computers: The period of fourth generation was from 1971-1980. Computers of fourth generation used Very Large Scale Integrated (VLSI) circuits. VLSI circuits having about 5000 transistors. VLSI technology used Very cheap and very small size Portable and reliable Concept of internet was introduced High-level languages like C, C++, DBASE etc., were used in this generation. 8  5th generation Fifth Generation Computers: The period of fifth generation is 1980- till date. In the fifth generation, VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components. High-level languages like C and C++, Java,.Net etc., are used in this generation. ULSI technology Development of artificial intelligence (AI), Natural language processing (NLP). Advancement in Parallel Processing Some computer types of this generation are: Desktop, Laptop and Notebook 9  Categories Of Computers Categories Of Computers Supercomputers.  Mainframes.  Servers Personal Computer. 10  Categories Of Computers Supercomputers: Is the fastest, most powerful computers and the most expensive.  Capable of processing more than 100 trillion instructions in a single second. They are used mostly in scientific and industrial research, by the government, and by very large organizations for controlling their networks.  Weather forecasting, oil exploration, telephone network design, 11  Categories Of Computers Mainframes: Is a large, expensive, powerful computer that can handle hundreds or thousands of connected user simultaneously through a technique called Timesharing. It store a huge amounts of data, instructions and information  ex. A timesharing system allows travel agents all over the country to make reservations using the same computer and the same flight information at the same time. Ex: University System. 12  Categories Of Computers Mainframes: Most major corporations use mainframes for business activities. Used by large organizations, such as banks and airlines, for big computing jobs. Users communicate with a mainframe using a computer terminal. 13  Categories Of Computers Servers: Controls access to HW, SW and other resources on a network. Provides a centralized storage area for program, data, information. Support from 2 to several thousand connected computers at the same time. People use PC or terminals to access data, info., and programs on it. Terminal is a device with monitor, keyboard and memory. 14  Categories Of Computers Personal Computers (PC): - It’s a computer that can perform all of its input, processing, output and storage activities by itself. There are 2 types of personal computer Notebook Computers -- Fits on your hand or lap. Desktop Computers -- Fits entirely on or under desk - Businesses use personal computers for word processing, accounting and for running spreadsheet and database 15 management applications.  Processing cycle Information Processing Cycle: Computers read incoming data called input , process the data, and display outgoing information called output. Data is a collection of unprocessed item, which can include text, numbers, images, audio and video. Information conveys meaning and useful to people. Processing Procedures that convert input data to output information. 16  components of computers 1-Hardware- H/W A group of machines in a computer system. 2-Software (programs) – S/W The instructions that tell the computer what to do and how to do it. 17  2-Software- S/W The Components of Software: There are two categories of software : 1. System Software: Consists of programs that control or maintain the operations of the computer and its devices. It’s serves as interface between the user and the computer 2. Application software: consists of programs designed to assist users with personal tasks. 18  Computer Components and von Neumann architecture All types of computers follow the same basic logical “von Neumann Architecture” and perform the following five basic operations for converting raw input data into information useful to their users. 19  Von Neumann architecture Another major characteristic of the von Neumann architecture is that the units that process information are separate from the units that store information. There are five components of the von Neumann architecture: 1) The memory unit that holds both data and instructions 2) The arithmetic/logic unit that is capable of performing arithmetic and logic operations on data 3) The input unit that moves data from the outside world into the computer 4) The output unit that moves results from inside the computer to the outside world 5) The control unit that acts as the stage manager to ensure that all the other components act in concert. 20