Introduction To Computers PDF

# **Chapter 1** ## Introduction To Computers ### 1.1 History #### Introduction - Computers are a tool in every sphere of human life. - They are bringing many changes in industry, government, education, medicine, scientific research, law, service and even art like music, movies and paintings. - The...

# **Chapter 1** ## Introduction To Computers ### 1.1 History #### Introduction - Computers are a tool in every sphere of human life. - They are bringing many changes in industry, government, education, medicine, scientific research, law, service and even art like music, movies and paintings. - The areas of application of computers are confined only by the limitation of creativity and imagination. - A child might define a computer as capable of producing a combination of radio, movie and television. - A computer is capable of performing millions of instructions in a few seconds with high accuracy. - It can be used for automatic calculations or controlling operations expressible in numerical or logical terms. - Computers perform assigned tasks quickly, do not get bored and can store information for later use. #### Early History - Humans have always needed to perform arithmetic like counting using fingers, stones, pebbles and beads. - Early civilizations developed number systems to keep track of astronomical cycles, business etc. - Computing means 'an act of calculating'. - After the invention of manual calculating tools, the concept of using electronic gadgets for computations was introduced and computers were born. - The evolution of computers has passed through a number of stages. #### Computer - A computer is an electronic machine capable of performing basic operations like addition, subtraction, multiplication, division, etc. ### 1.2 Data, Information and Program #### Data - Data can be explicitly encoded in a computer language. - It can be manipulated through processing. - Data is usually used to make meaningful information. - Data can be represented in textual, numerical, graphic, canographic, narrative, or audiovisual forms. #### Information - Information is processed facts, derived from data. - Stored facts are stored in a database. - Data is transformed into information. #### Program - A computer program (or a set of programs) is designed to systematically solve a problem. - The programmer determines the program requirements, develops the logic, and writes instructions for the computer in a programming language that the computer understands. - Problem solving is the act of defining a problem, understanding its requirements, and arriving at a workable solution. ### 1.3 Hardware and Software #### Introduction - Computers are machines associated with both hardware and software. #### 1.3.2 Computer Hardware - Hardware is all the physical components of a computer. - The major computer components include: - **Input devices:** The input devices accept data in a form understandable by the computer and send it to the processor. Common input devices are: keyboard, mouse, scanner, etc. - **The Processor (CPU):** The processor, formally called the Central Processing Unit (CPU), is the brain of a computer. It has electronic circuitry that manipulates input data into information. - **Memory:** Memory is where the CPU fetches instructions and data. It is also called primary memory. - **Storage:** Storage usually stores data and program information permanently. It is also called secondary storage. - **Output Devices:** Output devices show the results of processing. Common output devices are: monitor, printer, plotter, etc. - **Peripheral equipment:** Peripheral equipment includes all input, output and secondary storage devices. #### 1.3.3 Computer Software - Software is a set of planned, step-by-step instructions that makes something meaningful. - Computer software is classified into two categories: - System Software - Application Software #### System Software - System software consists of general programs written for a computer. - These programs provide the environment to run application programs. - System software comprises programs which interact with the hardware at a basic level. - They are the basic necessity of a computer system for its proper functioning. - System software serves as the interface between hardware and the user. - Examples of system software are: Operating systems, compilers and utility programs. ##### Operating Systems - Operating systems are the most important type of system software. - They manage the overall operations of a computer. - Each computer must have an operating system to run other programs. - Common operating systems include DOS, Unix, Linux and Windows. ##### Compilers - Compiler software translates the source program (user written program) into an object program (binary form). - Specific compilers are available for computer programming languages such as FORTRAN, COBOL, C, etc. #### Application Software - Application software consists of programs designed to solve user problems and accomplish specific tasks. - Application software manages hardware devices, controlled by system software. - Examples of specific applications include a survey system, word processing software, weather forecasting programs, etc. ##### Application Packages - The application software packages are commonly used for specific tasks. - Some common application packages include: - **Word processing software:** Word processing software is used for creating, editing, formatting, storing and printing text and graphics. Some common word processors include Microsoft Word, WordStar, WordPerfect, etc. - **Spreadsheet software packages:** Spreadsheet software packages are used to manipulate numbers, perform repetitive numeric calculations, use related formula, and create graphics and charts. Some common spreadsheet software packages include: Lotus 1-2-3, Excel, etc. - **Database Management System:** Data management systems are a collection of programs that enable users to store, modify, and extract information from a database. Common database management systems include: Computerized banking, Automated Teller Machines, Airlines and Railway reservations, etc. ### 1.4 Types of Computers #### Introduction - Classification of electronic computers may be based on either their principles of operation or their configuration. #### Classification based on Principles of Operation - Computers can be classified into three categories based on principles of operation: Analog computers, Digital computers and Hybrid Computers. #### Analog Computers - Analog computers deal with a continuous range of values. - They are generally used to deal with physical variables such as voltage, pressure, speed, etc. - They give approximate results. #### Digital Computers - A digital computer operates on digital values like numbers. - It uses the binary number system which uses only two digits 0 and 1. - Digital computers are designed using electronic logic circuits and are suitable for solving problems in engineering and technology. - Digital computers are designed using digital signals. - They provide more accuracy than Analog computers. #### Hybrid computers - Hybrid computing systems combine the desirable features of analog and digital computers. - They are mainly used for automatic operations of complicated physical processes and machines. - They use analog-to-digital and digital-to-analog converters to transform data values. #### Classification of Computers based on Configuration - Based on performance capacity, digital computers are classified into different types: Supercomputers, Mainframe computers, Mini computers and Micro computers. #### Classification of Digital Computers - Digital computers are classified as followed: - **Super Computers:** These are the mightiest and most expensive computers. They can process billions of instructions per second. Supercomputers are used to solve intensive numerical computations, such as: scientific simulations, weather forecasting, drug discovery and 3D graphics. - **Mainframe Computers:** Previously, these computers were known as big iron computers. They were developed to handle the processing and storage of large volumes of data for businesses. They are also cost-efficient for businesses. - **Mini Computers:** Mini computers are in decreasing demand today due to the evolution of more powerful personal computers. They are smaller than mainframe computers with limited storage capacity. - **Micro Computers:** The invention of the microprocessor led to the creation of micro computers. These are smaller and cheaper than mainframe computers. Micro computers are further classified as: - **Workstations:** These are high-performance and expensive micro computers, typically used for specialized tasks such as graphic design and engineering applications. - **Personal Computers (PCs):** These are the most commonly used computers, usually used for general purposes. PCs are further classified as: - **Desktop PCs:** Desktop PCs are compact computers that are placed on a desk. They are usually the most powerful type of PC. - **Laptop Computers:** These are portable computers with built-in keyboards, monitors and battery power. - **PDA (Personal Digital Assistants):** PDAs are small handheld computers with touch-sensitive screens, used for tasks such as scheduling, note-taking, and web browsing.