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History of Computing
• The synthesis of ideas underlying the general-purpose digital computer was achieved by Charles Babbage (1791-1871) • A working model of a "DIFFERENCE ENGINE” was produced in 1822. It was steam powered, and calculated mathematical tables. 2 Charles Babbage • Babbage then conceived an "analytical engine" with a storage, an arithmetic unit to perform calculations, and a punched-card input and output. • He spent most of the rest of his life (unsuccessfully) trying to build and perfect the machine, which was called by many of his contemporaries, "Babbage's folly.” Alan Turing (1912- 1954) • British Mathematician who did fundamental work on the theory of modern computer science. • Defined a simple but elegant mathematical model of a general purpose computer, now called the Turing Machine, and used it to prove what was possible or impossible for computers to do. ... Read more » |
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CLASSIFICATION OF COMPUTERS
Computer can be classified based on the way they operate or represent data. On the basis, there are three types, namely: * Analogue Computer. * Digital Computer. * Hybrid Computer. a. ANALOGUE COMPUTERS: There are computers that are used for measuring changes in physical state of a thing. It represents data in terms of Physical measures or quantities such as temperature, speed, volume and weight. Examples of analog computers and related equipment are car speedometer, measuring scale, thermometer, liquid dispenser (fuel pump) and electric meter, analog wristwatch, aero plane speedometer. etc. b. DIGITAL COMPUTERS: These are types of computers that are used for counting and calculating. They use discrete forms or binary systems (0s and 1s) to represent data. They store data in terms of digits (numbers). As a matter of fact, anything that counts number produces integers and series of numbers ... Read more » |
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COMPUTER GENERATIONS
•THE FIRST COMPUTERS WERE RESULTS OF WORLD WAR 2 DEVELOPMENTS, AIMED AT MILITARY USES •1944 AIKEN AT HARVARD MARK 1: FIRST ELECTROMECHANICAL DIGITAL COMPUTER (ELECTROMAGNETIC RELAYS -- MAGNETS OPEN AND CLOSES METAL SWITCHES). THE "FIRST GENERATION:” VACUMN TUBES •1946: ENIAC (Electronic Numerical Integrator and Computer) •FIRST ELECTRONIC DIGITAL COMPUTER, CONSTRUCTED WITH 17,000 VACUUM TUBES. EIGHT FEET TALL AND 80 FEET LONG. • EXTERNAL (WIRED) PROGRAM. •ENIAC could do 333 multiplications per second and cost the equivalent of $5- $10 million 4 SECOND GENERATION •USED SEMICONDUCTOR TRANSISTOR CHIPS DEVELOPED AT BELL LABS •1955 : IBM COMPUTER WITH 2000 TRANSISTORS. BY 1959, DELIVERIES MADE THE VACUMN TUBE COMPUTERS OUTMODED. INCLUDED VERY LARGE MAINFRAMES, SUCH AS THE IBM 7090, AND SMALLER MACHINES, SUCH AS THE IBM 1401. THIRD GENERATI ... Read more » |
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Computer Software
Software is the set of instructions, often called a program that controls the operation of a computer system. It tells the computer what to do, how and when to do it. Software can be specially developed for a particular field such as education, entertainment, communication, networking, utility etc. People that develop software are often called Programmers Types of Software A. System software: A specialized program that coordinates and controls the basic internal operation or function of the computer system. They also enable application software or other programs to run properly, for example operating system (Window 2000, Window Xp). B. Application Software: This allows the user to perform a specific task on the computer. They are ready – made program written in a standardize form packages and widely available which can be bought off the shelf in a computer shop. For example Microsoft word, Corel Draw, Adobe Photosh ... Read more » |
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Number Bases
The Arithmetic and Logical Unit (ALU) and related operations. ALU can add, subtract, multiply and divide numbers. The number of digits in a particular number system is called the BASE. The four (4) numbering system commonly used with micro computer are the binary, octal, decimal and hexadecimal. The binary numbering system uses only two digits i.e. zero (0) and one (1). The octal numbering system is the base 8 numbering system and the digits involved are 0,1,2,3,4,5,6 and 7. The decimal numbering system is the base 10 numbering system. The digit involved are 0,1,2,3,4,5,6,7,8 and 9. The hexadecimal or the base 16 numbering system has sixteen digit namely 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F. The letter A,B,C,D,E,F represent the natural numbers i.e. 10, 11, 12, 13, 14, 15 respectively. The base written as a subscript and enclosed in bracket. For example the 1101(2), 6573(8), 8963(10) and&nb ... Read more » |
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Operating System
Definition of Operating System Operating system can be referred to as Os, it is the software that controls the basic internal operations of a computer system, and coordinates the hardware activities. The operating system is the first program that is loaded whenever the computer is turned on; it provides the platform on which other applications programs will run. It is sometimes regarded as the supervisor. The operating system usually resides insides the computer (memory and hard disk) and is very important to the computer system such that without it, the computer will not work. Examples of Operating System * Microsoft Disk Operating System (MS-DOS) * Graphic User Interface Operating System (GUI) e.g. Window 98, Window 2000, Window Xp etc. * Macintosh Operating System (Mac Os) * Linux – Examples of an operating system that allows multiple users to use the computer at the same time or different time. * U ... Read more » |
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Introduction to Computer Programming
Programming involves writing the instructions to enable a computer to do a specific task. These instructions have to be written according to the rules of the particular programming language chosen for the task. Principles of good Programming The aim of computer programming is to transform a description of a user’s problem and an approach to its solution into form whereby it may be executed by a computer. The principles include: * Simplicity: The programmer language enables the programmer to state the computational solution to a specified problem in a notation which is both formal and human-intelligible. * Portability: The programming language is machine independent. Program can be written without prior knowledge of the machine on which they are run. Also, having run on one machine, they can be transported to run on other machines. * Accuracy: The prog ... Read more » |
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FORTRAN LANGUAGE
CLASSES OF DATA Computer programs, regardless of the language in which they are written, are designed to manipulate data of some kinds. CONSTANTS and VARIABLES, and their terms are used in FORTRAN in almost the same sense as in mathematics. CONSTANTS A constant is a quantity whose value does not change during program execution. It may be of numeric, characters, or logical type. INTEGER CONSTANTS - A is integer constant is literally an integer, i.e., a whole number without a decimal point. It may be zero or any positive or negative value. RULES FOR FORMING INTEGER NUMBERS 1. No decimal point 2. No fractional values. 3. Used as counter, exponents and identification number. 4. Results of integer arithmetic reduced to next-lower integer. 5. In general, the maximum magnitudes is 231- 1 a 10 digit number (depending on computers but some used 9 digits) 6. Remainders resulting from division are l ... Read more » |