UNIT I : COMPUTER FUNDAMENTALS Structure 1.1. Introduction 1.2. Objectives 1.3. What are computers? 1.4. Characteristics of a computer 1.5. Classification of Computers 1.5.1 Purpose Based Classification 1.5.2 Function Based Classification 1.5.3 Classification of Computers According to Size 1.6 Parts of a Computer 1.6.1 Key Board 1.6.2 Mouse 1.6.3 Monitor 1.6.4 Central Processing Unit 1.6.5 Functional Units 1.7 Other Input Devices 1.8 Other Output Devices 1.9 Primary and Secondary Devices 1.10 Let Us Sum up 1.11 Unit End Exercises 1.12 Answers to Check your Progress 1.13. Suggested Readings 1.1. Introduction : Computers play a vital role in every field. Computers have changed the way we work, in all types of profession and the computer technology has a deep impact on education too. Therefore, in the recent years, the role of computers in education has been given a lot of prominence. Computer education forms a part of the school and college curricula, a sit is important for every individual today, to 1 have the basic knowledge of computers. The advantages of computers in education include an efficient storage and rendition of information, quick information processing and very importantly the saving of paper. Computer teaching plays a key role in the modern systems of education. Students find it easier to refer to the Internet than searching for information in fat reference books. The process of learning has gone beyond learning from prescribed textbooks. Today, aspirers can satisfy their thirst for knowledge by means of the Internet. It is easier to store information on computers than maintaining hand-written notes. A life without computers would seem almost unimaginable for many. Today, computers are a part of almost every industry. They are widely used in networking, information access, data storage and the processing of information. The importance of computers is evident today and having the perfect know-how of computers can only propel one‘s career in the right direction. The present day computers are not only compact, extremely powerful and versatile but are also low priced, commonly accessible and easy to use. The computer has, indeed become an integral part of our daily life. Most importantly, the society at large is rapidly overcoming its initial hesitation and is all set to exploit the full potential of this new tool. Parallel developments in the field of telecommunications have opened up unique opportunities. The application of computers in education though started late, but has recently made deep inroads in this area. The conventional teaching methodology has undergone tremendous change and has radically modified the role of a teacher. This has generated a wealth of ideas, experience and resource material. So much so, that "Computer in Education" has emerged as a rigorous discipline in its own right. In recent years, computer studies" have become an essential part of school curriculum even at the primary level. However, there is growing realisation that it is not learning about computers as such but knowing what to do with computers that is going to make all the difference. This unit will introduce to you about the fundamentals of computers such as the parts, classification, characteristics, input and output devices of computers. 2 1.2 Objectives of the Unit: After learning this unit you will be able to list out the characteristics of computers. describe the classification of computers explain the parts of computers give the difference between primary and secondary devices say the different kinds of primary and secondary devices discuss the other input and output devices 1.3 What are computers? Computers are electronic machines that perform tasks or calculations according to a set of instructions, or programs. The term ‗computer‘ is derived from the Latin term ‗computare‘, which means to calculate. Computer can not do anything without a Program. It represents the decimal numbers through a string of binary digits. The Word 'Computer' usually refers to the Central Processor Unit plus Internal memory. Charles Babbage is called the "Grand Father" of the computer. The First mechanical computer designed by charles Babbage was called Analytical Engine. It uses read-only memory in the form of punch cards. The first fully electronic computers, introduced in the 1940s, were huge machines that required teams of people to operate. Compared to those early machines, today's computers are amazing. Not only are they thousands of times faster, they can fit on your desk, in your lap, or even in your pocket. 1.4 Characteristics of a computer A computer is an electronic computing device which performs the execution according to the given set of instructions called program. It accepts the data, processes it and produces the information. Let us identify the major characteristics of a computer. These can be discussed under the headings of speed, accuracy, diligence, versatility and memory. 3 Speed As you know computer can work very fast. It takes only few seconds for calculations that we take hours to complete. Suppose you are asked to calculate the average monthly income of one thousand persons in your neighbourhood. For this you have to add income from all sources for all persons on a day to day basis and find out the average for each one of them. Do you know your small computer can finish this work in few seconds? The weather forecasting that you see every day on TV is the results of compilation and analysis of huge amount of data on temperature, humidity, pressure, etc. of various places on computers. It takes few minutes for the computer to process this huge amount of data and give the result. You will be surprised to know that computer can perform millions (1,000,000) of instructions and even more per second. Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second) or nano-second (10-9 part of a second). From this you can imagine how fast your computer performs work. Accuracy Suppose some one calculates faster but commits a lot of errors in computing. Such result is useless. There is another aspect. Suppose you want to divide 15 by 7. You may work out up to 2 decimal places and say the dividend is 2.14. I may calculate up to 4 decimal places and say that the result is 2.1428. Some one else may go up to 9 decimal places and say the result is 2.142857143. Hence, in addition to speed, the computer should have accuracy or correctness in computing.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. Diligence A computer is free from tiredness, lack of concentration, fatigue, 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. If there are surplus amount of executions to be made then each and every execution 4 will be executed at the same time. They can perform their assigned task without taking any refreshment. Due to this capability it overpowers human being in routine type of work. Versatility It means the capacity to perform completely different types of work. You may use your computer to prepare payroll slips. Next moment you may use it for teaching and evaluation. In our day to day life computers has been a part, with their extended flexibility they are used, all over the world. They can be used as personal computers, for home uses, for business oriented tasks, weather forecasting, space explorations, teaching, railways, banking, medicine etc. All Modern computer can perform different kind of tasks simultaneously. Computers seem capable of performing almost any task, provided that the task can be reduced to series of logical steps. For example, a task such as preparing a payroll or controlling the flow of traffic can be broken down into a logical sequence of operations. Yet the computer itself has only limited ability and, in the final analysis, actually performs only four basic operations: It exchanges information with the outside world via I/O devices, It transfers data internally within the CUP, It performs the basic arithmetical operations, It performs operations of comparison. In one sense, then, the computer is not versatile because it is limited to four basic functions. Yet, because so many daily activities can be reduced to an interplay between these functions, it appears that computers are highly ingenious. Programming is the craft or reducing a given problem into an interplay between these few operations. Automation A computer is much more than an adding machine, calculator or check-out till, all of which require human operators to press the necessary keys for the operations to be performed. Once a program is in the computer's memory, the individual instructions are then transferred, one after the other, to the control unit 5 for execution. The CPU follows these instructions until it meets a last instruction which says 'stop program execution'. Storage Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data. The Computer has an in-built memory where it can store a large amount of data.