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Nội dung text Unit I - Introduction to Computer – Computer Fundamentals and Application.pdf

www.ckundan.com.np 1 Unit I: Introduction to Computer – Computer Fundamentals and Application Definition of Computer: The word "computer" is derived from the Greek word "compute" which means "to calculate". A computer is an electronic device which can be reprogrammed to take input from the user, process them by using CPU "Central Processing Unit" and give output in the human readable and understandable form and even store the output for future use. It can process both numerical and non-numerical (arithmetic and logical) calculations. The only language supported by computer system is "Binary System" or "Machine Language". The Machine Language is represented by 0's and 1's. How A Computer Works? A computer takes data input from real world by keyboard or mouse. The input data is converted into machine language before being processed. The CPU "Central Processing Unit" then processes the input data utilizing available resources. The result thus obtained is converted to human readable form, which may be displayed on monitor or print hardcopy by printer or listen sound through speaker. The working principle of computer can be summarized as input, process and output cycle. IPO Cycle: Data/Instruction Invisible Result [Input Devices] [Processor] [Output Devices] - Keyboard - CPU (CU + ALU) - Moniter - Mouse - Printer - Scannar - Speaker - Digital/web cam - Plotter Fig: Computer working process Input Process Output
www.ckundan.com.np 2 History of Computers: The history of computer starts from 4000 years ago. History of computer means the gradual change in the concept over a long period of time. Around fifth century, Hindu philosophers developed a new method of counting from 0 to 9. Counting the numbers from 0 to 9 can be performed with the help of fingers. The development of counting started from the development of simple counting device called ABACUS. Age of Mechanical Calculating Era: 1. Abacus: It is believed that abacus was the earliest counting device invented by human being. In fact, the oldest surviving abacus was used in 3000 B.C. by the Babylonians. The Chinese abacus was called ‘suan pan’ which means counting board. An abacus consists of rectangular frames containing a number of rods or wire which is divided into two unequal parts called earth and heaven. The lower part contains 5 beads/rings and upper part contains 2 beads/rings in each wire. By moving the beads/rings, it is used for counting as well as to find addition and subtraction. 2. Napier’s Bone: John Napier was a great Scottish mathematician. He invented ‘Principle of Logarithm’ in 1614 A.D. then based on his own principle, he invented a simple device containing 10 rods made of ivory sticks marked with numbers in 1617 A.D. That device was called Napier’s Bone and people can use it for faster multiplication and division.
www.ckundan.com.np 3 3. Schickard’s Calculating Clock: The first gear driven calculating machine was probably the calculating clock, named by its inventor, the German Professor Wilhelm Schickard in 1623 A.D. This device got little publicity because Schickard died soon afterward in the bubonic plague. 4. Slide Rule: Based on the principle of John Napier (Principle of Logarithm), William Oughtred an English mathematician made a simple device called slide rule in 1624 A.D. People could use it for faster multiplication and division. It was used in the 1960’s by the NASA engineers of the Mercury, Gemini and Apollo programs which landed men on the moon. 5. Pascaline: Pascaline was invented by Blaise Pascal in 1642 A.D. He invented pascaline to help his father who was tax collector. Pascaline had some cogs and gears rotating in complement to each other and it could do addition and subtraction up to 8 digits. Multiplication and division were also done by repeated addition and subtraction respectively. The car speedometer used the very same mechanism. Later a computer programming language was called ‘Pascal’ to honor Blaise Pascal for his great contribution.
www.ckundan.com.np 4 6. Stepped Reckoner: Gottfried Wilhelm von Leibniz was a great German mathematician. He managed to build a four function (addition, subtraction, multiplication and division) calculator in 1671 A.D. on the basis of Pascaline. He named that device “Stepped Reckoner” and he employed fluted drums having ten flutes arranged around their circumference in a stair-step fashion instead of gears. It could find square root too. Although the Stepped Reckorner employed the decimal number system, Leibniz was the first to advocate use of the binary number system which is fundamental to the operation of modern computers. 7. Jacquard’s Loom and Punch Card: In 1801 A.D. Joseph Marie Jacquard invented a power loom that could base its wave upon a pattern and automatically read form punched wooden cards, held together in a long row by rope. Later the same punched card technology was used for computer programming. Hence, he is remembered even in the history of computer. Jacquard’s technology was a real boon to mill owners, but put many loom operators out of work. Angry mobs smashed Jacquard Looms and once attacked Jacquard himself.

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