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COMPUTER FUNDAMENTALS, , INTRODUCTION, The term computer is derived from the word ‘compute’, which means ‘to calculate’., The impact of computers in our day-to-day life is tremendous and visible in all fields., Similarly in modern libraries, various activities are performed with the help of, computers. In this lesson, you will learn about works, and functions of a computer., , OBJECTIVES, ✓, ✓, ✓, ✓, ✓, , define a computer, identify its characteristics and functions;, list types of computers;, explain hardware and software;, recognize Input and Output units and devices; and, list types of operating systems;
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1.1 WHAT IS A COMPUTER, Computer is an electronic device which is capable of receiving information or data, and perform a series of operations in accordance with a set of operations. This, produces results in the form of data or information. Computer is a machine capable, of solving problems and manipulating data. It accepts and processes the data by, doing some mathematical and logical operations and gives us the desired output., Therefore, we may define a computer as an electronic device that transforms data, into information. Data can be anything like marks obtained by you in various, subjects, it can also be name, age, sex, weight, height, etc. of all the students in, your class or income, savings, investments, etc. of a country.
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1.2 BASIC COMPUTER OPERATIONS, A computer basically performs five major operations or functions such as:, ✓, ✓, ✓, ✓, ✓, , Accepts data or instructions by way of input., Stores data,, Processes data as required by the user,, Gives results in the form of output, and, Controls all operations inside a computer., , Each of these operations are discussed and shown in the figure given below:, , Fig.1.1 Basic computer Operations, , Let us know the details of basic computer operations., , 1.2.1 Input, This is the process of entering data and programs in the computer system. Therefore,, the input unit takes data from us to the computer in an organized manner for, processing., , 1.2.2 Storage, The data and instructions are saved/ stored permanently in storage unit. The storage
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unit performs the following major functions:, ✓ All data and instructions, before and after processing, are stored here,and, ✓ Intermediate results of processing are also stored here., , 1.2.3 Processing, The task of performing operations like arithmetic and logical operations is called, processing. The Central Processing Unit (CPU) takes data and instructions from, the storage unit and makes all sorts of calculations based on the instructions given, and the type of data provided. After this data is sent back to the storage unit., , 1.2.4 Output, This is the process of producing results from the data for getting useful information., The output produced by the computer after processing is stored inside the computer, before it is given to you in human readable form. The output is also stored inside, the computer for further processing., , 1.2.5 Control, Controlling of all operations like input, processing and output are performed by, control unit. It takes care of step-by-step processing of all operations inside the, computer.
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1.3 COMPUTER SYSTEM, In order to carry out its operations, a computer system is divided into three separate, units. They are:, ✓ Arithmetic logical unit,, ✓ Control unit, and, ✓ Central processing unit., All these three units are known as functional units., , 1.3.1 Arithmetic Logical Unit (ALU), The processing of the data and instructions are performed by Arithmetic Logical, Unit. The major operations performed by the ALU are addition, subtraction,, multiplication, division, logic and comparison. For processing, data is transferred, from storage unit to ALU. After processing, the output is returned back to storage, unit for further processing or for storing purpose., , 1.3.2 Control Unit (CU), The next component of computer is the Control Unit, which acts like the supervisor, seeing that things are done in proper way. The control unit determines the sequence, in which computer programs and instructions are to be executed. Activities like, processing of programs stored in the main memory, interpretation of the instructions, and issuing of signals for other units of the computer to execute them are carried, out by CU. It coordinates the activities of computer’s peripheral equipment which, include input and output devices. Therefore, it is the manager of all the operations, mentioned in the previous section., , 1.3.3 Central Processing Unit (CPU), The ALU and the CU of a computer system are jointly known as the central, processing unit (CPU). You may call CPU as the brain of any computer system. It, is just like brain that takes all major decisions, makes all sorts of calculations and, directs different parts of the computer functions by activating and controlling the, operations. The CPU (Central Processing Unit) is the device that interprets and, executes instructions., A computer system includes a computer, peripheral devices, and software.
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1.4 CHARACTERISTICS OF COMPUTER, Let us now identify the major characteristics of a computer. These are:, , 1.4.1 Speed, As you know computer can work very fast. It takes only a fraction of a second for, calculations that manually take hours to complete. It takes few minutes for the, computer to process huge amount of data and give the result., , 1.4.2 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, the computer. The errors in computer are mainly due to human and inaccurate data., , 1.4.3 Diligence, A computer is free from tiredness, lack of concentration, fatigue, etc. It can work, for hours without any error., , 1.4.4 Versatility, The computer is highly versatile. You can use it for a number of tasks simultaneously, such as, for inventory management, preparation of electrical bills, preparation of, pay cheques, etc. Similarly, in libraries computer can be used for various library, housekeeping operations like acquisition, circulation, serial control, etc. and also, by students for searching library books on the computer terminal., , 1.4.5 Power of Remembering, Computer has the power of storing large amount of information or data. Any, information can be stored and recalled whenever required for any numbers of years., It depends entirely upon you how much data you want to store in a computer and, when to retrieve or delete stored data.
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1.4.6 Dumb Machine with no IQ, Computer is a dumb machine and it cannot do any work without instructions from, the user. It performs the instructions at a tremendous speed and with great accuracy, as it has the power of logic. It is for you to decide what you want to do and in which, sequence. So, a computer cannot take decision of its own as human beings can take., , 1.4.7 Storage, The computer has an in-built memory where it can store huge amount of data. You, can also store data in secondary storage devices such as CDs, DVDs, and pen drives, which can be kept outside the computer and can be carried to other computers.
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1.5 GENERATION OF COMPUTERS, The history of computer development is in reference to different generation of, computing devices. The first-generation computers appeared in mid-1940s. The, present day computer, however, has undergone rapid changes for the last seven, decades. This period, during which the evolution of computer took place, can be, divided into five distinct phases known as Generations of Computers that are being, presented in the table given below: -
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1.6 TYPES OF COMPUTERS, Present day computers can be categorized as below:, , a) Super Computer, Supercomputers are fastest computers and are very expensive. These are employed, for specialized applications that require immense amounts of mathematical, calculations. For example, weather forecasting requires a supercomputer. Other uses, of supercomputers include animated graphics, fluid dynamic calculations, nuclear, energy research, and petroleum exploration., , b) Mainframe Computer, It is a very large and expensive computer and is capable of supporting hundreds, or, even thousands of users simultaneously. In the hierarchy that starts with a simple, microprocessor (in watches, for example) at the bottom and moves to, supercomputers at the top, mainframes are just below supercomputers. In some ways,, mainframes are more powerful than supercomputers because they support, simultaneous programs. But supercomputers can execute a single program faster, than a mainframe., , Fig.1.2: Mainframe Computer, , The main difference between a supercomputer and a mainframe is that, supercomputer channels all its power into executing a few programs as fast as
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possible, whereas a mainframe uses its power to execute many programs, concurrently., , c) Mini Computer, It is a mid-sized computer in size and power. It lies between workstations and, mainframes. In the past decade, the distinction between large minicomputers and, small mainframes have blurred. In general, a minicomputer is a multiprocessing, system capable of supporting from 4 to about 200 users simultaneously., , Fig.1.3:Minicomputer, , d) Micro Computer, i. Desktop Computer: a personal or micro-mini computer sufficient to fit on a, desk., , Fig.1.4: Desktop Computer
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ii. Laptop Computer: a portable computer completes with an integrated screen, and keyboard. It is generally smaller in size than a desktop computer and larger, than a notebook computer., , Fig.1.5:Laptop Computer, , iii. Palmtop Computer/Digital Diary /Notebook /PDAs (Personal Digital, Assistant): a hand-sized computer, Palmtop, does not have keyboard, but its, screen serves both as an input and output device., , Fig.1.6, , Fig.1.7, , Fig.1.8, , e) Workstations, It is a terminal or desktop computer in a network. In this context, workstation is, just a generic term for a user’s machine (client machine) in contrast to a “server”, or “mainframe.”
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1.7 HARDWARE AND SOFTWARE, 1.7.1 Hardware, Hardware refers to the physical equipment used for the input, processing, output, and storage activities of a computer system. It consists of mechanical and electronic, devices, which we are able to see and touch easily. Some of them are central, processing unit (CPU), primary storage devices, secondary storage devices, input, and output unit and communication devices. These are explained below: ✓ Central processing unit (CPU): It manipulates the data and controls the tasks, performed by the other components., ✓ Primary storage: It stores temporarily data and program instructions during the, processing., ✓ Primary memory (main memory): These are RAM (Random Access, Memory/Read-Write Memory), and ROM (Read-only-memory)., ✓ Secondary storage: These store data and programs for future use. These are, Hard Disk (Local Disk) and External Hard Disc, Optical Disks (CDR, CDRW,, DVD-R, DVD-RW ), Pen Drive, Memory Cards, etc., , Fig.1.10, , Fig.1.11, , Fig.1.12, , Secondary Storage Devices, Communication Devices: These are used for communication or flow of data from, one computer to another computer. Some of them are Modem, Switch, Router, TV, tuner card, etc., , Fig.1.13, , Fig.1.14, , Communication devices, , Fig.1.15
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1.7.2 Software, A computer cannot do anything on its own. It has to be guided by the user. We have, to give a sequence of instructions to the computer in order to do any specific job., Software is simply a computer program or a set of instructions. Software guides, the computer at every step indicating where to start and stop during a particular, job. The process of software development is called programming., , 1.7.2.1 Types of software, There are two types of software, namely, system software and application software., System software, System Software are general purpose programs designed to perform tasks such as, controlling all operations required to move data into and out of the computer. It, communicates with keyboard, printer, card reader, disk, tapes, etc. It also monitors, the use of various hardware like memory, CPU, etc. System software acts as an, interface between hardware and application software. Remember that it is not, possible to run application software without system software. Some of the system, software are Disc Operating System (DOS), Windows, Unix/Linux, MAC/OS X, etc., Application software, It is a set of programs, which are written to perform specific tasks of the users of, computer. Software is developed in high level languages to help the user, to get the computer to perform various tasks. Some of the application software are, MS Office, Macromedia (Dreamweaver, Flash, Freehand), Adobe (PageMaker,, Photoshop), LIBSYS, SOUL, WINISIS, KOHA, etc.
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1.8 INPUT AND OUTPUT UNIT, An input and output unit consists of two parts namely, input devices and output, devices. Normally, an Input and output unit can control one or more peripheral, devices. These units are explained below:, , 1.8.1 Input Unit, The data is entered / input into the computer through input devices. The input devices, translate the data / information from a natural language in which the user is working,, into the machine language which the computer can understand. Computer language, is in the form of binary code (0 and 1). Input devices are classified as follows:, ✓ Human data entry devices - keyboard, mouse, joystick, trackball, digitizing, labels and; pick devices - light pen touch screens., , Fig.1.16: Keyboard, , Fig.1.17: Scanner, , Fig.1.18: Web camera, , Fig.1.19: Joystick, , Input Devices, ✓ Source data entry devices (Audio input –speech recognition; video input digital camera; scanners - optical scanner OCR, OMR, MICR, Barcode, Reader). Pictures of some of the source data entry devices are given in Fig., 1.20 to 1.23., , Fig.1.20: Barcode Reader, , Fig.1.21: Microphone
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Fig.1.22: Optical Mark Reader, , Fig.1.23. Magnetic Card Reader, , Output Unit, The output unit accepts output data from computer via output devices and, transforms the data into human readable form. All the information inside the, computer is in the form of binary digits (0 and 1). Output devices convert them, to numbers, words, graphics, sound and motion which we can easily, understand., Output devices are classified as, ✓ Hard copy device (Printer, Plotter, Computer Output on Micro-film), ✓ Soft copy devices (Monitor, Visual Display Terminal, Video Output and Audio, Response). Output devices are shown in Fig. 1.24 to 1.27, , Fig.1.24: Monitor, , Fig.1.25: Printer, , Fig.1.26: Video Output, , Fig.1.27: Audio Unit
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1.9 OPERATING SYSTEM, An Operating System is a system software that acts as an interface between a user, and hardware of a computer. Modern operating systems usually feature a graphical, user interface which uses a pointing device such as mouse or keyboard for input., Operating Systems are viewed as resource managers that manage the resources of, a computer. The main resource is the computer hardware which is in the form of, processors, storage, input/output devices, communication devices, and data. A good, operating system should be efficient, reliable, take short time in execution of, programs, occupy small memory as small as possible., , The main Operating Systems are:, , 1. Network Operating System, ✓ WINDOWS 2000, ✓ Unix, ✓ Linux, , 2. Desktop Operating System, ✓ WINDOWS, ✓ DOS (Disc Operating System), ✓ Mac OS, , 3. Mobile Operating System, ✓ Palm OS, ✓ Pocket PC
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Some of the operating system are presented in the following table along with their, main characteristics:
