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UNIT-I

UNIT-I. Introduction To Computers. Introduction to Computer. Early days people use fingers for computing purpose. As years go, the computing needs also grew. This leads to the invention of calculators and computers.

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UNIT-I

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  1. UNIT-I Introduction To Computers

  2. Introduction to Computer • Early days people use fingers for computing purpose. • As years go, the computing needs also grew. This leads to the invention of calculators and computers. • The term computer is derived from the word compute, it means to calculate.

  3. Definition • Computer is an electronic device. It accepts data, process the data and gives the desired output. COMPUTER INPUT OUTPUT

  4. Basic functions or operations • Input • Processing • Output • Storing • Controlling

  5. Basic operations (Cont) • Input It is the process of getting the data from the user or from somewhere else into the computer to process. • Processing It is the process of converting the input to output.

  6. Basic operations (Cont) • Output It is the outcome or result of the process. • Storing It is the process of saving the data. so that it can be retrieved whenever needed.

  7. Basic operations (Cont) • Controlling It is the process of directing the sequence in which the operations to be performed.

  8. Applications of computer: • Business • Industry • Home • Education • Printing & publishing • Entertainment etc.,

  9. CHARACTERISTICS OF COMPUTER

  10. CHARACTERISTICS OF COMPUTER • Speed • Accuracy • Diligence • Versatility • Resource sharing • Storage

  11. CHARACTERISTICS OF COMPUTER (cont) • Speed The computer process the data extremely fast. (i.e.) in millions (1,000,000) of instructions and even more per second. A computer can perform a huge task in few sec where a human being may take hours or even days to complete the same task.

  12. CHARACTERISTICS OF COMPUTER (cont) • Accuracy The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.

  13. CHARACTERISTICS OF COMPUTER (cont) • Diligence A computer is free from tiredness, lack of concentration etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.

  14. CHARACTERISTICS OF COMPUTER (cont) • Versatility It means the capacity to perform completely different type of work. For example At a moment a computer can be used to draft a letter. Next moment it can be used print a document or play a music file etc.,

  15. CHARACTERISTICS OF COMPUTER (cont) • Resource sharing In organizations the computers are connected to form a network. The resources such as printers, scanner, plotters are connected to the network and it can be shared by the computers in the network.

  16. CHARACTERISTICS OF COMPUTER (cont) • Storage Computers are capable of storing huge amount of data and it can be located and retrieved very quickly. It uses storage devices such as hard disk to store huge amount of data.

  17. Evolution of Computers

  18. Evolution of Computers • Abacus The first calculating device called ABACUS was developed by the Egyptian and Chinese people. It consisted of sticks in horizontal positions on which were inserted sets of beads. It has a number of horizontal bars each having ten beads. Horizontal bars represent units, tens, hundreds, etc.

  19. Evolution of Computers (Cont) • Napier’s bones English mathematician John Napier built a mechanical device for the purpose of multiplication in 1617 A D. The device was known as Napier’s bones. • Slide Rule This machine could perform operations like addition, subtraction, multiplication, and division. It was widely used in Europe in 16th century.

  20. Evolution of Computers (Cont) • Pascal's Machine Blaise Pascal developed a mechanical calculating machine called Pascal’s calculating machine. It could add and subtract. The machine consisted of wheels, gears and cylinders. • Leibniz’s Machine The Pascal’s calculating machine can perform addition and subtraction but it could not perform multiply and division. Leibniz built a mechanical device that could both multiply and divide.

  21. Evolution of Computers (Cont) • Babbage’s Analytical Engine In the year 1823 that a famous English man Charles Babbage built a mechanical machine to do complex mathematical calculations. It was called difference engine. Later he developed a general-purpose calculating machine called analytical engine. Charles Babbage is called the father of computer.

  22. Evolution of Computers (Cont) • Electronic Calculator The electronic calculator used in 1960’s was run with electron tubes, Later it was replaced with transistors and as a result the size of calculators became too small. It can compute all kinds of mathematical computations. Some calculators have in-built programs to perform some complicated calculations.

  23. Generations of Computers

  24. Generations of Computers (Cont) First Generation Computers: • These computers were vacuum tube based machines. • They used magnetic drums for memory. • Input were fed into the computer using Punched cards • The size of these computers were very large and it produce more heat. • They lacked in versatility and speed. • They were more expensive.

  25. Generations of Computers (Cont) Second Generation Computers • Here the Transistorreplaced the bulky vacuum tubes. • Transistors are smaller than vacuum tubes and have higher operating speed. • Thus the size of the computer got reduced considerably. • Manufacturing cost was also very low.

  26. Generations of Computers (Cont) Third Generation Computers • These computers were based on Integrated Circuits(ICs) Technology. • A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. • So that the size of the computer got further reduced. • These Computers were small in size, low cost, large memory and processing speed is very high.

  27. Generations of Computers (Cont) Fourth Generation Computers • It uses large scale Integrated Circuits(LSIC) built on a single silicon chip called microprocessors . • Later very large scale Integrated Circuits (VLSIC) replaced LSICs • These computers are called microcomputers. • Thus the size of the computer got reduced. • The personal computer (PC) are comes under the Fourth Generation.

  28. Generations of Computers (Cont) Fifth Generation Computer • The speed is extremely high in fifth generation computer. • The concept of Artificial intelligence has been introduced to allow the computer to take its own decision. • It is still in a developmental stage .

  29. Classification of Computer

  30. Classification of Computer • Microcomputer • Mini Computer • Mainframes • Supercomputer

  31. Classification of Computer Computer Microcomputer Supercomputer Mainframes Mini Computer N/W Servers Desktop Smart phones Laptops

  32. Classification of Computer (Cont) Microcomputer • Microcomputer is at the lowest end of the computer range in terms of speed and storage capacity. Eg: Desktop, Laptop, Tablet PC, Smart Phones.

  33. Classification of Computer (Cont) Mini Computer • This is designed to support more than one user at a time. • It possesses large storage capacity and operates at a higher speed. • This type of computer is generally used for processing large volume of data in an organisation. • Eg:Servers in Local Area Networks (LAN).

  34. Classification of Computer (Cont) Mainframes • They operate at very high speed, having very large storage capacity and can handle the work load of many users. • They are generally used in centralised databases.

  35. Classification of Computer (Cont) Supercomputer • They are the fastest and most expensive machines. • They have high processing speed compared to other computers. • They have also multiprocessing technique. • Supercomputers are mainly being used for whether forecasting, biomedical research, and other areas of science and technology

  36. Classification of Computer (Cont) • The computers can also classified based on the hardware design as follows • Analog computer. • Digital computer. • Hybrid computer.

  37. BASIC ORGANISATION OF COMPUTER

  38. Basic organisation of computer CONTROL INPUT MEMORY OUTPUT ALU

  39. Basic organisation of computer • INPUT • The input unit is used to information or instruction to the computer. • It accept the information or instruction from user or from some where else. • Convert it to a computer understandable form and send it to the computer. Eg:Keyboard,mouse,Joystick,MICR, etc,.

  40. Basic organisation of computer (cont) • CENTRAL PROCESSING UNIT (CPU) • It is the heart of the computer. • It performs all operations. • It contains the followings • CONTROL UNIT • ALU • MEMORY

  41. Basic organisation of computer (cont) • CONTROL UNIT • It controls all other units in the computer. • It directs the sequence in which operations to be performed. • It also controls the flow of data between various units.

  42. Basic organisation of computer (cont) • ARITHMETIC & LOGICAL UNIT • It performs all arithmetic & logical operations. • i.e. arithmetic operations like addition, subtraction, multiplication, division etc,. And logical operations like AND,OR,NOT etc,.

  43. Basic organisation of computer (cont) • MEMORY UNIT • Place for holding the information. • Types • Primary • Secondary • Primary memory is used to store temporary data.Eg:RAM,ROM etc,. • Secondary memory is used to store information permanently. Eg:Hard disk.

  44. Basic organisation of computer • OUTPUT • The output unit is used to display the result of the process. Eg:Monitor,printer,speakers, etc,.

  45. Components of Computers

  46. Components of Computers • Hardware The physical components present in the computer. • Software It is a collection of programs and it can perform some operaions.

  47. Components Present inside the cabinet • Motherboard • Processor • SMPS • Disk drives • RAM & ROM etc,.

  48. Types of Memory MEMORY SECONDARY PRIMARY SEQ.ACESS RANDOM ACCESS

  49. Primary Memory: It is used to store data temporary.

  50. RAM • Random Access Memory • It is possible to randomly select and use any location of the memory. • It is a volatile memories i.e. It loose their content when the power is switched off

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