Fundamentals Of Computer And Information Technology PDF

1. INTRODUCTION TO COMPUTER C omputers are an integral part of our lives. Wherever we are—sitting in our homes, working in the office, driving on roads, sitting in a movie hall, staying in a hotel, etc.—our lives are directly or indirectly affected by the computers. In thi...

1. INTRODUCTION TO COMPUTER C omputers are an integral part of our lives. Wherever we are—sitting in our homes, working in the office, driving on roads, sitting in a movie hall, staying in a hotel, etc.—our lives are directly or indirectly affected by the computers. In this era of information, we are dependent on the storage, flow and processing of data and information, which can only be possible with the help of computers. The purpose of this chapter is to introduce you to the “computer”. 1.1 INTRODUCTION Nowadays, computers are an integral part of our lives. They are used for the reservation of tickets for airplanes and railways, payment of telephone and electricity bills, deposit and withdrawal of money from banks, processing of business data, forecasting of weather conditions, diagnosis of diseases, searching for information on the Internet, etc. Computers are also used extensively in schools, universities, organizations, music industry, movie industry, scientific research, law firms, fashion industry, etc. The term computer is derived from the word compute. The word compute means to calculate. A computer is an electronic machine that accepts data from the user, processes the data by performing calculations and operations on it, and generates the desired output results. Computer performs both simple and complex operations, with speed and accuracy. This chapter discusses the history and evolution of computer, the concept of input-process-output and the characteristics of computer. This chapter also discusses the classification of digital computers based on their size and type, and the application of computer in different domain areas. Page 1 of 118 1.2 DIGITAL AND ANALOG COMPUTERS A digital computer uses distinct values to represent the data internally. All information is represented using the digits Os and 1s. The computers that we use at our homes and offices are digital computers. Analog computer is another kind of a computer that represents data as variable across a continuous range of values. The earliest computers were analog computers. Analog computers are used for measuring of parameters that vary continuously in real time, such as temperature, pressure and voltage. Analog computers may be more flexible but generally less precise than digital computers. Slide rule is an example of an analog computer. This book deals only with the digital computer and uses the term computer for them. 1.3 CHARACTERISTICS OF COMPUTER Speed, accuracy, diligence, storage capability and versatility are some of the key characteristics of a computer. A brief overview of these characteristics are: Speed The computer can process data very fast, at the rate of millions of instructions per second. Some calculations that would have taken hours and days to complete otherwise, can be completed in a few seconds using the computer. For example, calculation and generation of salary slips of thousands of employees of an organization, weather forecasting that requires analysis of a large amount of data related to temperature, pressure and humidity of various places, etc. Accuracy Computer provides a high degree of accuracy. For example, the computer can accurately give the result of division of any two numbers up to 10 decimal places. Diligence When used for a longer period of time, the computer does not get tired or fatigued. It can perform long and complex calculations with the same speed and accuracy from the start till the end. Page 2 of 118 ========================================================= Storage Capability Large volumes of data and information can be stored in the computer and also retrieved whenever required. A limited amount of data can be stored, temporarily, in the primary memory. Secondary storage devices like floppy disk and compact disk can store a large amount of data permanently. Versatility Computer is versatile in nature. It can perform different types of tasks with the same ease. At one moment you can use the computer to prepare a letter document and in the next moment you may play music or print a document. Computers have several limitations too. Computer can only perform tasks that it has been programmed to do. Computer cannot do any work without instructions from the user. It executes instructions as specified by the user and does not take its own decisions. SUMMARY ✓ Computer is an electronic device which accepts data as input, performs processing on the data, and gives the desired output. A computer may be analog or digital computer. ✓ Speed, accuracy, diligence, storage capability and versatility are the main characteristics of computer. Page 3 of 118  2. THE COMPUTER SYSTEM C omputers is an electronic device that accepts data as input, processes the input data by performing mathematical and logical operations on it, and gives the desired output. The computer system consists of four parts (1) Hardware, (2) Software, (3) Data, and (4) Users. The parts of computer system are shown in Figure. Computers, in simple words, are machines that perform a set of functions according to their users’ directions. Going by this definition, several electronic devices, from laptops to calculators, are computers. A computer comprises of some basic elements. These include hardware, software, programs, data and connectivity. No computer can function in the absence of these elements. Apart from these elements, a computer system comprises of three basic components. These components are responsible for making computers actually function. Let’s take a look at them in detail. Page 4 of 118 ========================================================= 2.1 Components of Computer Hardware When we talk of computer hardware, the three related terms that require introduction are—computer architecture, computer organization and computer design. Computer architecture refers to the structure and behavior of the computer. It includes the specifications of the components, for example, instruction format, instruction set and techniques for addressing memory, and how they connect to the other components. Given the components, computer organization focuses on the organizational structure. It deals with how the hardware components operate and the way they are connected to form the computer. Given the system specifications, computer design focuses on the hardware to be used and the interconnection of parts. Different kinds of computer, such as a PC or a mainframe computer may have different organization; however, basic organization of the computer remains the same. A computer consists of three main components: 1) Input/Output (I/O) Unit. 2) Central Processing Unit (CPU). 3) Memory Unit. The computer user interacts with the computer via the I/O unit. The purpose of I/O unit is to provide data and instructions as input to the computer and to present relevant information as output from the computer. CPU controls the operations of the computer and processes the received input to generate the relevant output. The memory unit stores the instructions and the data during the input activity, to make instructions readily available to CPU during processing. It also stores the processed output. This section discusses the hardware components of the computer and the interaction between them. 2.1.1 INPUT-OUTPUT UNIT An I/O unit is a component of computer. The I/O unit is composed of two parts— input unit and output unit. The input unit is responsible for providing input to the computer and the output unit is for receiving output from the computer. Page 5 of 118 Input Unit The input unit gets the data and programs from various input devices and makes them available for processing to other units of the computer. The input data is provided through input devices, such as—keyboard, mouse, trackball and joystick. Input data can also be provided by scanning images, voice recording, video recording, etc. Irrespective of the kind of input data provided to a computer, all input devices must translate the input data into a form that is understandable by the computer, i.e., in machine readable form. The transformation of the input data to machine readable form is done by the input interface of input device. In brief, the input unit accepts input data from the user via input device, transforms the input data in computer acceptable form using input interface for the input device and provides the transformed input data for processing. Input devices allow users and other applications to input data into the computer, for processing. The data input to a computer can be in the form of text, audio, video, etc. The data is entered manually by the user or with minimal user Page 6 of 118 ========================================================= intervention. An input device is a hardware device that transfers data to a computer system and allows us to control it. WHAT IS AN INPUT DEVICE? The electromagnetic devices that accept data or a set of instructions from the outside world and then translate that data into machine-readable and understandable form are known as input devices. Computer input devices serve as an interface between the outside world and the computer for proper communication. When the users enter data using various input devices, the data can be saved in computer memory for further processing and preparation. Using the output devices, the intended and calculated results can be acquired when the processing and handling are completed. An input device transmits data to a computer and allows you to communicate with it and control it. Different Types of Input Devices Keyboard For entering data into a computer, the keyboard is the most common and commonly used input device. It contains various keys for entering letters, numbers, and characters. Although there are some additional keys for completing various activities, the keyboard layout is identical to that of a standard typewriter. It is generally available in two different sizes 84 keys or 101/102 keys and for Windows and the Internet, it is also available with 104 keys or 108 keys. It is connected to a computer system with the help of a USB or a Bluetooth device. Page 7 of 118 The keys on the keyboard are: Numeric Keys: These keys are used to enter numeric data and move the cursor. It is typically made up of 17 keys. Keyboard Shortcuts: These keys include the letter keys (A-Z) and the number keys (09). Control Keys: The pointer and the screen are controlled by these keys. It comes with four directional arrow keys. Control keys include Home, End, Insert, Alternate(Alt), Delete, Control(Ctrl), and Escape. Special Keys: Enter, Shift, Caps Lock, NumLk, Tab, and Print Screen are some of the special function keys on the keyboard. Function Keys: The 12 keys from F1 to F12 are on the topmost row of the keyboard. Generally, the keyboard is of three types: QWERTY Keyboard AZERTY Keyboard DVORAK Keyboard Characteristics of Keyboard: ✓ The keyboard has various functions keys for a different purpose ✓ Instead of using the mouse, we can utilize the arrow keys on the keyboard to do the same purpose as the mouse. ✓ The main keyboard, cursor keys, numeric keypad, and function keys are the four primary components of a keyboard. ✓ Keyboards are more affordable. Mouse The mouse is the most used pointing device. While clicking and dragging, the mouse moves a little cursor across the screen. If you let off of the mouse, the Page 8 of 118 ========================================================= cursor will come to a halt. You must move the mouse for the computer to move; it will not move on its own. As a result, it’s a device that accepts input. Or we can say that a mouse is an input device that allows you to control the coordinates and movement of the on-screen cursor/pointer by moving the mouse on a flat surface. The left mouse button can be used to pick or move items, while the right mouse button displays additional menus when clicked. It was invented in 1963 by Douglas C. Engelbart. Generally, the mouse is of four types: Trackball Mouse Mechanical Mouse Optical Mouse Wireless Mouse Characteristics of the mouse: ✓ A mouse is used to move the cursor on the screen in the desired direction. ✓ A mouse allows users to choose files, folders, or multiple files or text or, all at once. ✓ Hover over any object with the mouse pointer. ✓ A mouse can be used to open a file, folder, etc. You must first move your pointer to a file, folder, and then double-click on it to open or execute. Joystick A pointing device used to move the cursor around the screen is the joystick. Both the bottom and top ends of the stick have a spherical ball affixed to them. A socket contains the lower spherical ball. You can adjust the joystick in all directions. Trackballs became quite popular in laptops and PCs since they fit neatly inside the case and take up less room when in use. They are Page 9 of 118 more precise and long-lasting than a mouse, which is why they are still utilized. It is invented by C.B.Mirick. Characteristics of Joystick: ✓ It’s utilized to regulate the cursor’s position across a display screen. ✓ It’s utilized in computer games to move the characters and symbols around. ✓ It commonly features one or more push buttons, the condition of which can be controlled by the computer as well. Light Pen A light pen is a pointing device that has the appearance of a pen. It can be used to draw on the monitor screen or to pick a menu item. In a small tube, a photocell and an optical system are housed. The photocell sensor element determines the screen location and sends a signal to the CPU when the tip of a light pen is moved across a monitor screen while the pen button is pressed. Characteristics of the light pen: ✓ When drawing graphics, a light pen comes in very handy. ✓ Objects on the display screen are selected with a light pen. Scanner A scanner is a type of input device that works in the same way as a photocopier. It’s used when there’s data on paper that needs to be transferred to the computer’s hard disc for further processing. The scanner collects images from the source and translates them to a digital version that can be saved on the hard disks. These graphics can be changed before they are printed. Generally, the scanner is of five types: Page 10 of 118 ========================================================= Flatbed Scanner Handheld Scanner Sheetfed Scanner Drum Scanner Photo Scanner Characteristics of Scanner: ✓ You can scan film negatives via a scanner if there is a transparent media adaptor. ✓ A scanner may also scan low-quality or non-standard-weight paper. ✓ The scanners are adaptable, allowing you to scan a wide range of items regardless of their size. You can scan small items as well as large documents if you can locate them. OCR OCR stands for Optical Character Recognition in its full form. OCR is a computer reading technique that reads numbers, characters, and symbols. OCR is a technique for recognizing text in documents that have been scanned into digital form. Optical character recognition (OCR) refers to a device that reads printed text. Character by character, OCR scans the text, converts it to a machine- readable code, and saves it into the memory of the system. OCR also functions as a scanner, scanning documents, photos, images, and handwritten text and storing the information in memory, which may then be compared to previously stored data. Characteristics of OCR: ✓ The technology offers a complete solution for form processing and document capture. Page 11 of 118  ✓ It has capabilities for defining shapes, scanning, image pre-processing, and identification. Barcode Reader A bar code reader is a device that reads bar-coded data (data that is represented by light and dark lines). To label things, number books, and so on, bar-coded data is often utilized. It could be a standalone scanner or a component of one. A barcode reader is a device that reads barcodes and extracts data from them. The code bar is used to read the bar code printed on any goods. By impacting light beams on barcode lines, a barcode reader identifies existing data in barcodes. Characteristics of Barcode Reader: ✓ When a card is inserted, auto-start barcode scanners begin scanning immediately. ✓ Reading indicators give the user confirms that the card has been swiped correctly. ✓ It’s simple to use, simply hold your phone up to the code and scan it. Web Camera A webcam is an input device since it records a video image of the scene in front of it. It can either be incorporated inside the computer (for example, a laptop) or connected via USB. A webcam is a small digital video camera that is connected to a computer. Because it can capture pictures and record video, it’s also known as a web camera. Characteristics of Web Camera: ✓ Webcams are used to allow individuals to see one other while chatting online. This is formally referred to as ‘teleconferencing’. ✓ Because webcams can take a picture only if movement is detected in the scene in front of them, they are commonly utilized in burglar alarms and other security systems. Page 12 of 118 ========================================================= ✓ Hundreds of webcams can be found all around the world, each pointing to a fascinating scene such as the exterior view of a facility in the Arctic or Niagara Falls. The webcam is connected to a computer that regularly sends an image to an internet server. After that, people connect to the server to view the most recent image. Graphic Tablet A graphics tablet, also known as a digitizing tablet, is a computer input device that allows users to draw drawings and graphics by hand, much like they would with a pencil and paper. A graphics tablet is a flat surface on which the user can draw a picture with the help of an attached stylus, which is a pen-like drawing device. Characteristics of a Graphics Tablet: ✓ The graphics tablet is a pressure-sensitive tablet that is controlled by a pen. ✓ Drawing, writing, inserting, etc. can be done with the pen. ✓ It provides more precision and the ability to monitor (than a touchscreen). Page 13 of 118 Digital Camera Digital camera is a device that takes photographs as input. Images are saved on memory cards as data. It comes with an LCD display that allows users to view and review photographs. A digital camera contains photosensors that record the light that enters into the camera lens. So, when the light strikes the photosensors, they return the electric current and this electric current is used to create images. Characteristics of Digital Camera: ✓ Users can immediately examine images and movies on the LCD screen. ✓ All the photos can be stored in the storage device. ✓ Users can select and choose the images they want to develop. ✓ Easily portable & takes less space. Page 14 of 118 ========================================================= Output Unit The output unit gets the processed data from the computer and sends it to output devices to make them available to the user of computer. The output data is provided through output devices like display screen, printer, plotter and speaker. The processed data sent to the output device is in a machine understandable form. This processed data is converted to human readable form by the output interface of output device. In brief, the output unit accepts output data from computer via output device, transforms the output information to human readable form using the output interface of output device and provides the transformed output to user. In addition to input devices and output devices, some devices function as both input and output devices. The I/O devices provide the input to computer as well as get output from computer. The I/O devices are used by both the input unit and the output unit. Hard disk drive, floppy disk drive, optical disk drives are examples of I/O devices. Page 15 of 118 Output Devices are those devices which show us the result after giving the input data to a computer system. Output can be in different forms like image, graphic audio, video, etc. What is an Output Device? Any peripheral that accepts data from a computer and prints, projects, or reproduces it is known as an output device. The output may be audio, video, hard copy – printed paper, etc. Output devices convert the computer data to human understandable form. We give input to the computer using input devices and the computer performs operations on the data and displays the output to the user using the output device. How Does an Output Device Work? In order to show the output, an output device uses a signal it receives from the computer to accomplish a task. An output device’s fundamental operation is listed below as an illustration. If you enter ‘Hi Geeks’ on a computer keyboard (input device), the computer receives the signal. Once the input has been processed by the computer, an output device—a monitor—is signalled. The display (output) of the ‘Hi Geeks’ on the screen occurs once the monitor receives the signal. Another example of an output device is a printer, which might print that ‘Hi Geeks’ if it were supported. If the computer was working and had no output device attached, you could still type ‘Hi Geeks’ on the keyboard and it would still be processed. Without an output device, you couldn’t see what happened or verify the input, though. Different Types of Output Devices The various output devices are as below: Page 16 of 118 ========================================================= 1. Monitor A computer’s principal output device is a monitor, often known as a visual display unit (VDU). It displays the processed data like text, images, videos, audios, etc. It makes images by arranging microscopic dots in a rectangular pattern, known as pixels. The sharpness of an image is determined by the number of pixels. There are two types of monitor viewing screens: ▪ Cathode-Ray Tube (CRT): This type of monitor is based on a cathode ray tube. In which the cathode ray tube generates a beam of electrons with the help of electron guns they strike on the inner surface of phosphorescent of the screen to generate images. The CRT monitor holds millions of phosphorus dotes in three different colors, i.e., red, blue, and green. These dots glow when the beam struck on them and create an image. The main parts of the CRT monitor are the electron gun, fluorescent screen, glass envelope, deflection plate assembly, and base. ▪ Display on a Flat Panel Monitor with a Cathode-Ray Tube (CRT): A flat-panel display is a type of video display with less volume, weight, and power consumption than a CRT. They can be put on the wrist or hang on the wall. Calculators, video games, monitors, laptop, and graphical displays all use flat-panel displays. ▪ Plasma Monitor: It is also a flat panel display but it is based on plasma display technology. In a plasma monitor, a small cell is present in between two glass surfaces and these cells contain a solution of noble gases and mercury. So when the electricity supply on the gas present in the cell converts into plasma and produces UV light that creates an image. It is much better than an LCD monitor. The resolution of this monitor is also high up to 1920 x 1920. It has a good contrast ratio, high refresh rate, etc. Characteristics of Monitor: Page 17 of 118  ▪ Resolution pixels: Pixels are the smallest element of any image ▪ Size: The size of the monitor is diagonal measurement of a desktop screen is typically 14 to 25 inches. ▪ Refresh Rate: Total number of times per second that an image on a display is repainted or refreshed. 2. Printer Printers are information output devices that allow you to print data on paper. Or in other words, it is an output device that creates a hard copy of the processed data or information. Printers are divided into two categories: ▪ Impact Printer: In impact printers, characters are printed on the ribbon, which is then smashed on the paper. Or we can say that such type of printer uses a print head or hammer to print the data on the paper. Here to print the paper the hammer or print head strikes an ink ribbon against the paper and the character starts printing. Some of the types of impact printers are: ✓ Dot matrix printer ✓ Daisy wheel printer ✓ Line printer ✓ Chain printer ▪ Impact printers have the following characteristics: ✓ Extremely low consumable costs. ✓ Fairly noisy ✓ It’s perfect for large-scale printing because of its inexpensive cost. ✓ Physical contact with the paper is required to form an image. ▪ Non-Impact Printers: Non-impact printers print characters without the use of a ribbon. These printers are often known as page printers because they print a full page at a time. Some of the types of non-impact printers are: ✓ Laser printer Page 18 of 118 ========================================================= ✓ Inkjet printer ▪ Non-impact printers have the following characteristics: ✓ Quicker. ✓ They don’t produce much noise. ✓ Superior quality. ✓ Supports a wide range of fonts and character sizes. 3. Plotter A plotter is a device that prints high-quality graphics in a variety of color formats. It works in a similar way to a printer, although it has more advanced features. It is used to print large maps, architectural drawings, large-format printing, and create pictures, 3D postcards, advertising signs, charts, and various designs of the internal structure of building machines, as well as create pictures, 3D postcards, advertising signs, charts, and various designs of the internal structure of building machines. Characteristics of Plotter: ✓ Large size prints can be taken via plotters. ✓ It is slow and expensive. 4. Projector A projector is a device that allows users to project their output onto a large area, such as a screen or a wall. It can be used to project the output of a computer and other devices onto a screen. It magnifies texts, photos, and movies using light and lenses. As a result, it’s an excellent output device for giving presentations or teaching big groups of people. Page 19 of 118 Characteristics of Projector: ✓ They are lightweight, and one person can easily take them out of the box, connect them, and hang an image on the wall. ✓ Projectors can be the most cost-effective option for large-screen video in your home. ✓ A small projector mounted on a back shelf or bookcase, or mounted on the ceiling, takes up no area on the floor. It is barely visible when it is not in use. 5. Speakers Speakers are connected to computers to allow sound to be output. For the working of speakers, sound cards are required. From simple two- speaker output devices to surround-sound multi-channel sets, speakers come in a variety of shapes and sizes. They take audio input from the computer’s sound card and output sound waves as audio output. Characteristics of Speakers: ✓ Speakers are available in a wide range of qualities and prices. ✓ Small, plastic computer speakers with low sound quality are often included with computer systems. 6. Headphones To hear the sound, use earbuds with your computer, laptop, or smartphone. It enables you to hear the sound without causing any inconvenience to others. To translate electronic signals into sounds without causing inconvenience to others. They can be wired or wireless and can be connected to computers, laptops, mobile phones, etc. They are connected with the devices via Bluetooth. Page 20 of 118 ========================================================= Characteristics of Headphones: ✓ Stereo phones and headsets are other names for them. ✓ Earphones or earbuds are the names for the in-ear variants. ✓ The term headset denotes a combination of headphones and a microphone used for two-way communication, such as using a telephone. 7. Sound Card Sound cards are computer output devices that are inserted into the computer. A sound card, either external or internal, is required to produce sound on any computer (built-in). An external sound card enables for better overall sound generation and is required for wide and clear sound recording, as well as sound without noise and interference. Characteristics of Sound Card: ✓ To listen speakers or headphones, to play games, watch movies, listen to music, or use audio and video conferencing, we use an internal sound card. ✓ Frequency is a sound card parameter that represents the number of signals the card processes per unit of time. The frequency is expressed in hertz. The frequency of most sound cards is 96 or 192 kHz. ✓ Synthesizers and a variety of electronic musical instruments, such as drums and keyboards, can be connected to your computer using a sound card with standard musical instrument digital interface (MIDI) connections. Page 21 of 118 8. Video Card An extension card via which a computer can transfer graphical data to a video display device like a TV, or monitor. It processes photos and video, as well as other functions that the CPU generally does. As they have a good processing capability and video RAM, Gamers utilize video cards. Characteristics of Video Card: ✓ Heat sinks are required for video cards with high performance as they generate a lot of heat. ✓ Also known as graphics card and require software installation in addition to the hardware. ✓ When working with huge files, video cards supply a significant quantity of video-only memory that frees up CPU resources, allowing the system to run more effectively. 9. Speech Synthesizer A speech synthesizer is a computerized device that takes in data, interprets it, and generates audible words. It might be a computer card, a box connected by a cable, or software that works with the computer’s sound card. Characteristics of speech synthesizer: ✓ Any text, predetermined input can be translated into audible speech. ✓ For people who are unable to talk or have impaired vision, it can provide digital verbal communication. ✓ It takes in data, interprets it, and generates sound output. Page 22 of 118 ========================================================= 10. GPS The Global Positioning System (GPS) is a radio-based satellite navigation system that uses radio signals to pinpoint a specific position. The sender sends a radio signal to satellites, which collect data such as time, location, speed, and other variables and deliver it to the reception computer for analysis. Because this processed data can be evaluated to obtain information, it is considered as an output device. Characteristics of GPS: ✓ GPS satellites constantly communicate their position and time. ✓ Solar storms, high storm cover, and other factors impair GPS equipment. ✓ The Global Positioning System (GPS) is based on the mathematical idea of trilateration. ✓ The GPS works independently of telephonic or internet reception and does not need the user to send any data, however, to improve accuracy both technologies can be used. Both the Input and Output Devices of the Computer There are so many devices that contain the characteristics of both input and output. They can perform both operations as they receive data and provide results. Some of them are mentioned below. USB Drive USB Drive is one of the devices which perform both input and output operations as a USB Drive helps in receiving data from a device and sending it to other devices. Page 23 of 118 Modem Modems are one of the important devices that helps in transmitting data using telephonic lines. CD and DVD CD and DVD are the most common device that helps in saving data from one computer in a particular format and send data to other devices which works as an input device to the computer. Headset The headset consists of a speaker and microphone where a speaker is an output device and a microphone works as an input device. Facsimile A facsimile is a fax machine that consists of a scanner and printer, where the scanner works as an input device and the printer works as an output device. 2.1.2 Central Processing Unit (CPU). The full form of CPU is Central Processing Unit. It is a brain of the computer. All types of data processing operations and all the important functions of a computer are performed by the CPU. It helps input and output devices to communicate with each other and perform their respective operations. It also stores data which is input, intermediate results in between processing, and instructions. A Central Processing Unit is the most important component of a computer system. A CPU is a hardware that performs data input/output, processing and storage functions for a computer system. A CPU can be installed into a CPU socket. These sockets are generally located on the motherboard. CPU can perform various data processing operations. CPU can store data, instructions, programs, and intermediate results. Page 24 of 118