Title Computer-eBook-Rekib.pdf ✅

INTRODUCTION A COMPUTER is an electronic device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically. Characteristics of Computers  Speed: The speed of computation is very high as the signals pass at the speed of light. Thus, millions of calculations can be done in a second.  Accuracy: As computers work on inbuilt software programs, there is no scope for human errors and are hence, highly accurate.  Information and Storage: A computer can store a large amount of data or instructions in its memory which can be retrieved at point of time.  Other characteristics include: Consistency, Automatic Operation, and Flexibility. History of Computers  Father of Computer: Charles Babbage  Father of Modern Computer Science: Alan Tuning  First Un-programmable Electronic Digital Computer: Atanas off Berry Computer (ABC)  First Purpose Electronic Digital Computer: Electronic Numerical Integrator and Calculator (ENIAC) GENERATIONS OF COMPUTERS: First Generation (1946 - 1959)  Used vacuum tubes & batch processing OS  Machine & Assembly Languages used  Examples: ENIAC, EDVAC, UNIVAC, IBM-701, IBM-650 Second Generation (1959-1965)  Used transistors  OS: Multi-Bag remaining, Time sharing  Memory: Magnetic cores, magnetic tapes and disks  Used assembly and high-level languages like FORTRAN, COBOL, Algol  Examples: IBM 1620, IBM 7094, CDC 1604 Third Generation (1965-1971)  Used ICs  OS: Remote processing, Time-sharing, Real-time, Multi-programming  Used High-level languages FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68  Examples: IBM-360 series, Honeywell-6000 series, PDP, IBM-370/1683 Fourth Generation (1971-1980)  VLSI Circuits Used  Memory: Semiconductor and Winchester disk  High level Languages: Fortan 77, Pascal, Cobol used REKIB AFREDI 2 Visit:www.rekibafredi.com
 Examples: DEC 10, STAR 1000, PDP 11, Super Computers (CRAY-1, CRAY-X- MP) The present generation of computers is the Fifth Generation of computers, i.e. 1980-till date. The computers use ultra large scale integration (ULSI). High level languages like C++, Java, NET, etc. are used. Some examples are: laptop, desktop, ultrabook etc. TYPES OF COMPUTERS 1. Personal Computers:  Small, inexpensive computer for personal use  Also called a micro-computers  Popularly used at homes for playing games and/ or surfing the Internet.  Used for word processing, desktop publishing, spreadsheet and database management applications 2. Mini Computers  These were designed for specific tasks but have now lost popularity due to the advent of Pcs. 3. Mainframes  These are expensive and large sized computers  Are capable of supporting hundreds of users simultaneously  Used for specific large scale applications 4. Super Computers  Powerful, expensive and the fastest computers  Used for applications that require large amounts of mathematical computations  For example: weather forecasting, fluid dynamics, graphic design etc. COMPUTER FUNDAMENTALS A computer system has four basic components. Parts of a Computer System  Hardware: represents the physical and tangible components of the computer (keyboard, mouse, monitor etc.).  Software: is a set of electronic instructions called programs that make the computer perform tasks.  Data: the raw facts, which the computer stores and reads in the form of numbers.  Users: the people who make use of a computer to obtain certain results/ outcomes. REKIB AFREDI 3 Visit:www.rekibafredi.com
DATA PROCESSING CYCLE OF A COMPUTER A computer's data processing cycle comprises of the following three steps: 1. Input:  It refers to the commands given by a user to the computer using input devices like mouse, keyboard etc. 2. Processing:  In this step, the command given by the user are carried out by the computer. Thus, this step produces a more useful form of data at the end. 3.Output:  The result of the processing that is stored and displayed to the user by means of output devices like monitor, printer etc. is called output. REKIB AFREDI 4 Visit:www.rekibafredi.com