Object Oriented Programming (CSC241 ) Introduction to ICT INTRODUCTION TO ICT Lecture#1 COMSATS University Islamabad, Abbottabad Campus TABLE OF CONTENTS Basic Definition of Information Technology (IT) Computer Technology & Communications Technology Role of IT in Society Computing Models Turing Model Von Neumann Model Input Devices Keyboard Pointing & Touch Devices Game Controllers Optical Input Devices Audio and video input Devices Output Devices Monitors Audio Output Printers & Plotters Tutor::Dr. Fiaz Gul Khan COMSATS University Islamabad Abbottabad Campus 2 BASIC DEFINITION OF INFORMATION TECHNOLOGY (IT) Definition 1: Information technology (IT) is the technology that uses computing with high-speed communication links to spread information from one place to another. COMSATS University Islamabad Abbottabad Campus 3 CONT… The interconnection of computers enable people to send and receive information Communication links are also used to communicate with different people in the world The world has become a global village due to IT Information play important role in every field of life improve standard of life Used for solving different problems IT has enabled different type of organizations and institutions to be a part of digital convergence COMSATS University Islamabad Abbottabad Campus 4 COMPUTER TECHNOLOGY & COMMUNICATIONS TECHNOLOGY Information and communications technology (ICT) is an extensional term for information technology (IT) Definition: All devices , networking components, applications and system that combined allow people and organization to interact in the digital world. COMSATS University Islamabad Abbottabad Campus 5 COMPONENT OF ICT COMSATS University Islamabad Abbottabad Campus 6 ROLE OF IT IN SOCIETY IT play an important role in different filed of life: Education Finance Government Health Care COMSATS University Islamabad Abbottabad Campus 7 CONT… Science Publishing Travel Manufacturing COMSATS University Islamabad Abbottabad Campus 8 COMPUTING MODELS The idea of a universal computational device was first described by Alan Turing in 1937. He proposed that all computation could be performed by a special kind of a machine, now called a Turing machine. He based the model on the actions that people perform when involved in computation. Turing machines are theoretical concepts invented to explore the domain of computable problems mathematically and to obtain ways of describing these computations. Turing presented a mathematical description of such a machine, he was more interested in the philosophical definition of computation than in building the actual machine. COMSATS University Islamabad Abbottabad Campus 9 TURING MODEL • The Turing model is a better model for a general-purpose computer. • This model adds an extra element to the specific computing machine : the program. Fig 1.1: A single purpose computing machine Fig 1.2: A computer based on the Turing model • A program is a set of instructions that tells the computer what to do with data. • A program is a set of instructions written in a computer language. • The output data depend on the combination of two factors: the input data and the program. COMSATS University Islamabad Abbottabad Campus 10 CONT… Fig 1.3: The same program, different data COMSATS University Islamabad Abbottabad Campus 11 CONT… Fig 1.4:The same data, different programs COMSATS University Islamabad Abbottabad Campus 12 CONT… A universal Turing machine, a machine that can do any computation if the appropriate program is provided, was the first description of a modern computer. We need only provide the data and the program—the description of how to do the computation—to either machine. In fact, a universal Turing machine is capable of computing anything that is computable. COMSATS University Islamabad Abbottabad Campus 13 VON-NEUMANN MODELS Early computers (e.g. ENIAC) ran fixed programs; creating a new program for the computer required rewiring the machine. John von Neumann had the idea of storing the program inside the memory of the computer. Computers built on the Turing universal machine store data in their memory. Von-Neumann Architecture is one of the two most Computer Architecture Models which are used so common in the present-day IT field in computer systems. Around 1944–1945, John von Neumann proposed that, since program and data are logically the same, programs should also be stored in the memory of a computer. Fig 1: Von-Neumann Architecture COMSATS University Islamabad Abbottabad Campus 14 CONT… Fig 1.5: The Von Neuman model COMSATS University Islamabad Abbottabad Campus 15 CONT… Von-Neumann Architecture is otherwise called as Von-Neumann model or Princeton architecture and sometime even called as shared program model Properties of Von-Neumann Architecture 1. The stored program concept: The von Neumann model states that the program must be stored in memory. The memory of modern computers hosts both a program and its corresponding data. They are stored as binary patterns (a sequence of 0s and 1s) in memory. 2. Sequential execution of instructions A program is made of a finite number of instructions. They are executed sequentially. COMSATS University Islamabad Abbottabad Campus 16 A WORLD OF COMPUTERS Computers are everywhere COMSATS University Islamabad Abbottabad Campus 17 WHAT IS A COMPUTER? A computer is an electronic device, operating under the control of instructions stored in its own memory that can accept data, process the data according to specified rules, produce results, and store the results for future use. Collects data (input) Processing Produces information (output) COMSATS University Islamabad Abbottabad Campus 18 DATA AND INFORMATION Data is a collection of unprocessed items, which can include text, numbers, images, audio, and video. Information conveys meaning and is useful to people. COMSATS University Islamabad Abbottabad Campus 19 WHAT IS COMPUTER? COMSATS University Islamabad Abbottabad Campus 20 THE COMPONENTS OF A COMPUTER A computer contains many electric, electronic, and mechanical components known as hardware Input Device Output Device • Allows you to enter data and instructions into a computer • Hardware component that conveys information to one or more people System Unit • Case that contains the electronic components of the computer that are used to process data Storage Device • Records (writes) and/or retrieves (reads) items to and from storage media Communications Device • Enables a computer to send and receive data, instructions, and information to and from one or more computers or mobile devices COMSATS University Islamabad Abbottabad Campus 21 CONT… COMSATS University Islamabad Abbottabad Campus 22 ADVANTAGES AND DISADVANTAGES OF USING COMPUTERS Advantages of Using Computers Disadvantages of Using Computers Speed Health Risks Reliability Violation of Privacy Consistency Public Safety Storage Impact on Labor Force Communications Impact on Environment COMSATS University Islamabad Abbottabad Campus 23 TYPES OF COMPUTERS Analog Digital Hybrid COMSATS University Islamabad Abbottabad Campus 24 CATEGORIES OF COMPUTERS • Computers are classified on the basis of size, speed, processing power and price Personal computers Mobile computers and mobile devices Workstation Mini Computers Mainframes Supercomputers Embedded computers COMSATS University Islamabad Abbottabad Campus 25 PERSONAL COMPUTERS/MICRO COMPUTERS Personal Computers are used by individuals (Single user computer) Consists of processor, memory, one or more I/O devices, storage devices and communication devices Commonly used personal computers are: PCs (compatible with Windows)and Apple(compatible with Mac OS) COMSATS University Islamabad Abbottabad Campus 26 CONT… Major types of personal computers are : 1. 2. Desktop computer Portable computer Desktop computers : The most common type of personal computer Designed in a way all its components fits on the desk or table Performs a variety of tasks Portable computer Mobile personal computer that can be carried from one place to other Has I/O, storage and processing components integrated in a single unit Can receive power from a battery Types of portable computers are: Laptop, Ultrabook , Tablets etc COMSATS University Islamabad Abbottabad Campus 27 MOBILE DEVICES AND MOBILE COMPUTERS Mobile Devices Designed to hold in the hand Small screen Data are permanently stored on a special memory or on small storage media such as smart card Always powered by rechargeable battery system Types of mobile devices : Smartphone • Mobile Computers, Handheld computers, palm computer Personal computer you can carry from place to place Very small computers Personal Digital Assistants (PDA) Note taking or contact management Data can synchronize with a desktop COMSATS University Islamabad Abbottabad Campus 28 WORKSTATION Workstation is a computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other such types of applications which require a moderate amount of computing power and relatively high quality graphics capabilities. Workstations generally come with a large, high-resolution graphics screen, large amount of RAM, inbuilt network support, and a graphical user interface. Most workstations also have a mass storage device such as a disk drive, but a special type of workstation, called a diskless workstation, comes without a disk drive. Common operating systems for workstations are UNIX and Windows NT. Like PC, Workstations are also single-user computers. However, workstations are typically linked together to form a local-area network, although they can also be used as stand-alone systems. COMSATS University Islamabad Abbottabad Campus 29 CONT… COMSATS University Islamabad Abbottabad Campus 30 MINICOMPUTER It is a midsize computer. A minicomputer is a multi-processing system capable of supporting from up to 250 users simultaneously (multi-user computer) COMSATS University Islamabad Abbottabad Campus 31 CONT… Called midrange computers Power between mainframe and desktop Used in smaller organizations Users access through a terminal Example HP300 Prime 9955 COMSATS University Islamabad Abbottabad Campus 32 MAINFRAMES Called enterprise server of high-ended server Large in term of price, power and speed Consists of multiprocessor performed multiple tasks Used in large organizations Handle thousands of users simultaneously (Multi-User Computer) Users access through a terminal Large and powerful systems Example • IBM S-390 • IBM System Z10 • Uses Used in large organization such as bank, educational institute and government department e.g NADRA, flight schedules, ticket reservation system etc COMSATS University Islamabad Abbottabad Campus 33 SUPERCOMPUTER The most powerful computers Multi-user computer Handle large and complex calculations Process trillions of operations per second Found in research organizations Example Blue Gene Deep Blue Uses Used for weather predictions and atomic research etc. Also used in business and industry field COMSATS University Islamabad Abbottabad Campus 34 EMBEDDED COMPUTERS Designed for special purpose Function as a component in a larger product ▫ Small and limited hardware Example Home Devices: security monitoring, microwave ovens etc Electronics: DVD players, mobile etc Consumer Electronics •Mobile and digital telephones •Digital televisions •Cameras •Video recorders •DVD players and recorders •Answering machines Home Automation Devices •Thermostats •Sprinkling systems •Security monitoring systems •Appliances •Lights Automobiles •Antilock brakes •Engine control modules •Airbag controller •Cruise control Process Controllers and Robotics •Remote monitoring systems •Power monitors •Machine controllers •Medical devices Computer Devices and Office Machines •Keyboards •Printers •Faxes •Copiers COMSATS University Islamabad Abbottabad Campus 35 CONT… COMSATS University Islamabad Abbottabad Campus 36 COMPUTER COMPONENTS: INPUT DEVICES Computer Input Devices: Keyboard Pointing & Touch Devices Mouse, Trackball, Touch Pad, Pointing Stick, Touch Screen, Input pen Game Controllers Joy Stick, Gamepad Optical Input Devices Scanners , Barcode, MICR, OMR, OCR, Barcode Reader Audio Visual Devices Data Projectors, Microphones, Speakers Audio Input , Voice Input ,Digital Camera , Webcam , Sensor Input Devices Human Biology Input Devices COMSATS University Islamabad Abbottabad Campus 37 INPUT DEVICES The data and instructions given to the computer is known as input A hardware component used to enter data and instructions into computer is called input device The data is entered into the computer in different ways using different input devices Commonly used input devices are: keyboard, pointing devices, touch screen etc COMSATS University Islamabad Abbottabad Campus 38 KEYBOARD Most commonly used input device Data is mostly entered using keyboard Buttons on the keyboard are called keys The arrangement of keys on the keyboard is called keyboard layout Most popular keyboard layout is QWERTY The letters Q,W,E,R,T and Y appears on the top row of the main area of a keyboard The keys on the keyboard are often classified as follows: Numeric keypad: located on the right hand side of the keyboard Has arithmetic operators keys +,-,/ ,* Used in arithmetic operations Digits from 0 to 9 Also has Num Lock When NumLk key is off, the keyboard cannot be used to type number COMSATS University Islamabad Abbottabad Campus 39 CONT… Function Keys: F1 to F12 are located at the top of the board Used to perform special function Example: F1 key is used to get help in window Alphanumeric Keys: include all letters in alphabet (A-Z) and digits from 0-9 Backspace Key: used to delete single letter to the left of the curser Enter Key: used to enter commands or input data in the computer Caps Lock Keys: CapLock is a toggle key The character appear in uppercase if it is pressed If not pressed character appears in lower case Numbers and symbols are not affected Status light under CapLock turns on when it is pressed Tab Key: used to move the curser to the next tab stop Also used in dialog box to move from one option or field to another COMSATS University Islamabad Abbottabad Campus 40 CONT… Modifier Keys: used to modify the input of the other keys A specific key is pressed while holding down one of these keys to get the required result Different modifier keys are follows: 1. Ctrl Key: Ctrl key produce different results depending on the type of software Used in combination with other keys as shortcuts to some command Example: Ctrl+O is used to open a file 2. Alt Key: ALT key is used on combination with other keys to perform special functions In window-based programs, used to navigate menus and dialog boxes. Example: Alt+F4 is used to close a file 3. Shift Key: SHIFT key is used to type capital letter or symbols Curser Control Keys: consist of arrows keys, Home, End, Page Up, Page Down keys Used to move the curser within in the text or around the secrn COMSATS University Islamabad Abbottabad Campus 41 CONT… Different cursor control keys are as follows: 1. Home: Home key is used in word processing to move cursor to the top of the screen 2. End: End key is normally used in word processing to move the cursor to the right of the screen or to the end of screen or document 3. Arrows: The keys that move the cursor are called arrow keys. These keys have an up arrow, down arrow, a left arrow and right arrow 4. PageUp: used to move the cursor one page up on screen 5. PageDown: used to move the cursor one page down on screen COMSATS University Islamabad Abbottabad Campus 42 CONT… Special-Purpose Keys: These keys are used for special purpose and are as follows: 1. 2. 3. 4. Esc: Used to terminate command or current task Delete: used to delete a single letter to the right of the curser on the screen. Used to delete the selected object Insert: It is a toggle key used to switch between Insert Mode and Overtype Mode Print Screen: Used to capture everything that appears on the screen Scroll Lock: It lock or unlocks the cursor on screen in some programs Pause/Break: pause screen when information is too fast to read COMSATS University Islamabad Abbottabad Campus 43 TYPES OF KEYBOARD Different types of Keyboard are as follows: 1. Standard Keyboard: A standard keyboard is normally called QWERTY keyboard because the first six keys on the top row of letters on these keyboards are Q,W,E,R,T,Y 2. Wireless Keyboard: Keyboard that require no wire. It is also called as cordless keyboard. It is using radio signals range up to 100 feet 3. Portable Keyboard: A Keyboard that can easily attached or removed from a handheld computer 4. Ergonomic Keyboard: a keyboard is specially designed to reduce the chance of write injuries during typing. • Main goal of this keyboard is to provide comfort, efficiency and safety COMSATS University Islamabad Abbottabad Campus 44 ERGONOMIC KEYBOARD COMSATS University Islamabad Abbottabad Campus 45 CONT… Gaming Keyboard :Keyboard that is specially designed for playing games on the computer. Virtual Keyboard: Special keyboard. User types on optical-detectable surface or within the wireless area rather than pressing physical keys. COMSATS University Islamabad Abbottabad Campus 46 CONT… Keyboard Layouts QWERTY : Common layout QWERTZ :Used in Germany, Hungary and Czech Republic AZERTY :It is used by most French speakers based in Europe DVORAK :Alternative for QWERTY Dvorak layout uses less finger motion, increases typing rate, and reduces errors compared to the standard QWERTY COMSATS University Islamabad Abbottabad Campus 47 POINTING & TOUCH DEVICES A device with which you can control the movement of the pointer to select items on a display screen. A pointer is a small symbol that appear on the screen in GUI Types of pointing device: Based on rolling a ball Based on touching a surface Based on moving stick COMSATS University Islamabad Abbottabad Campus 48 CONT… Based on rolling a ball Example: Mouse Trackball Mouse: Mouse is a pointing device Used to input instructions with a pointer on the screen Mouse is moved on a flat surface to control the movement of the cursor Normally has two buttons These buttons are used to perform different tasks i.e. opening a program, selection of objects It may also include wheel Rolled with the figures to scroll the screen Connected with the computer through USB port or Wireless connection COMSATS University Islamabad Abbottabad Campus 49 CONT… Type of mouse 1. Machine Mouse/Wheel mouse: : Has a rubber or metal ball on its underside that can roll in all directions. Curser movement depends on the movement of the ball Mouse is normally used on mouse pad Mouse pad is a small pad of rubber or foam to provide easy movement of the mouse Protect mouse from dust and dirt 2. Optical Mouse/ Laser Mouse: No ball Emit light to detect the mouse movement Optical laser or sensors are used COMSATS University Islamabad Abbottabad Campus 50 CONT… 3. Wireless / Cordless Mouse: Does not require wire to work Transmit data using wireless technology like radio waves of infrared light waves 4. Air Mouse: Motion-sensing mouse Control media player, objects and slide shows by moving the mouse in a specific direction through air no need of surface Example: user can raise up to increase the volume of media player COMSATS University Islamabad Abbottabad Campus 51 CONT… 5. Touch Mouse: Touch-sensitive mouse Recognize touch gestures Detect clicks scroll movement etc COMSATS University Islamabad Abbottabad Campus 52 TRACKBALL Alternative to mouse Buttons similar to mouse Large rotating ball on the top Body of the trackball is not moves Ball is rolled with fingers Courser movement is controlled by rotating ball Advantage: take less space as compared to mouse COMSATS University Islamabad Abbottabad Campus 53 POINTING DEVICE Based on touching a surface Example: Touchpad Touch screen Pen Input Light pen Stylus COMSATS University Islamabad Abbottabad Campus 54 TOUCHPAD/TRACKPAD Small, flat surface over which user moves his fingers Touchpad also has one or more buttons near it Buttons work like mouse buttons Commonly used with notebook computers COMSATS University Islamabad Abbottabad Campus 55 TOUCH SCREEN A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area/Touch-sensitive display input device User touch different parts of the screen with fingers or stylus to input data Used in tablets, mobile device, ATM etc Laptops also have touch screen No need for external output device COMSATS University Islamabad Abbottabad Campus 56 PEN INPUT Mobile users usually input data using a device like pen User can draw and write on flat surface Devices used are pen input are: Stylus Digital pen/ Light pen Stylus: Made of plastic or metal Input is given with pressure Thinner because no internal electronics Need only screen Touch screen Used in many smart phones COMSATS University Islamabad Abbottabad Campus 57 CONT… Digital Pen: More functionality than a stylus Pressure sensitive Require special paper No work on touch screen Used in TabletPC COMSATS University Islamabad Abbottabad Campus 58 BASED ON MOVING STICKS Example: Joystick Gamepad Joy Stick Consist of base and a stick Stick moved in any direction To move the object around the computer screen Perform similar functions to a mouse or trackball Less comfortable and efficient Used for playing computer games COMSATS University Islamabad Abbottabad Campus 59 GAMEPAD/GAME CONTROLLERS A gamepad, also sometimes called joypad Refers to an input device used for gaming purposes. It is a video game controller that can be held with both hands and has multiple buttons on it to be pressed by the thumbs. Gamepads were first introduced with gaming console systems as a peripheral device to connect the user with the system. A gamepad is also known as a joypad. COMSATS University Islamabad Abbottabad Campus 60 OPTICAL INPUT DEVICES Optical input devices allow computers to use light as a source of input. Scanner is an example of optical input device. Other common optical input devices are magnetic ink character reader used for Magnetic Ink Character Recognition (MICR) Optical mark reader used for Optical Mark Recognition (OMR), Optical character reader for Optical Character Recognition (OCR) Barcode Reader. COMSATS University Islamabad Abbottabad Campus 61 SCANNERS Scanner is also known as optical scanner Light-sensitive input Read printed text, graphics and translate it in digital form Scanned image can be used for different purposes as follows: Displayed on screen Printed on the paper Sent through email Posted on web page Can be stored permanently for later us Quality of scanned image depends on the resolution Measured in dpi (dots per inch) Typically scanners scans at a resolution of 300 to 600 dpi Types of scanners Different types of optical scanners are: 1. Flatbed Scanner 2. Sheetfed Scanner 3. Handheld Scanners COMSATS University Islamabad Abbottabad Campus 62 CONT… Magnetic Ink Character Reader: MICR is used in banks to process large volumes of cheques. It is used for recognizing the magnetic encoding numbers printed at the bottom of a cheque. Optical mark reader: OMR is used to detect marks on a paper. OMR uses an optical mark reader to read the marks. The OMR reader scans the forms, detects the mark that is positioned correctly on the paper and is darker than the surrounding paper, and passes this information to the computer for processing by application software. For this, it uses a beam of light that is reflected on the paper with marks, to capture presence and absence of marks. OMR is widely used to read answers of objective type tests COMSATS University Islamabad Abbottabad Campus 63 CONT… Barcode Reader It is also called as Barcode Scanner Use laser beam to read bar code and translate them into digital signals Digital signals are further processed by the computer Barcode consist of vertical lines and shape of different width The bar code represent data that are identified the manufacturer and the item Used in shop and glossary stores COMSATS University Islamabad Abbottabad Campus 64 CONT… Optical Character Recognition (OCR) OCR is a technique for the scanning of a printed page, translating it, and then using the OCR software to recognize the image as ASCII text that is editable. OCR uses optical character reader for recognition COMSATS University Islamabad Abbottabad Campus 65 AUDIO AND VIDEO INPUT DEVICES Audio Input Devices: Process of entering any sound into the computer is called audio input It may include speech, music, or any other sound effect Audio van be entered through different devices such as microphone, tape player, CD/DVD players or radio Voice Input Device: The process of entering data by speaking into microphone attached to the computer is called voice input Microphone is attached to the computer with the help of sound card Faster way of entering data Many word processing applications provide the facility of voice input User speaks into the microphone an the application software write the spoken words COMSATS University Islamabad Abbottabad Campus 66 CONT… Microphone A microphone is a hardware peripheral that allows computer users to input audio into their computers. • MIDI Keyboard • A MIDI (Musical Instruments Digital Interface) keyboard is typically a piano-style user interface keyboard device used for sending MIDI signals to a computer. • MIDI information is sent to a computer that capable of reproducing an array of digital sounds or samples that resemble traditional analog musical instruments. COMSATS University Islamabad Abbottabad Campus 67 VIDEO INPUT DEVICES Used to digitize images or video from the outside world into the computer. Example: – Digital camera – Webcam – Optical scanner– Fingerprint scanner – Barcode reader Digital Camera: Input device, take pictures and store them as a digital image It store captured image on storage in the camera or some type of memory cards Quality of digital camera depends on its resolution Resolution describe the sharpness of an image Resolution is measures in megapixels COMSATS University Islamabad Abbottabad Campus 68 CONT… Webcam: Webcam is also called as PC video camera Used for following purposes Capture video or still image Send email and video attachment Make video telephone call Normally placed on the top of the monitor Most computers have built-in webcam COMSATS University Islamabad Abbottabad Campus 69 SENSOR INPUT DEVICES Input device that input data directly from the environment and store it in computer Used to detect speed, movement, pressure, temperature, wind etc Can be used to sense the weather conditions and earthquakes COMSATS University Islamabad Abbottabad Campus 70 HUMAN BIOLOGY INPUT DEVICES Biometric is a technology to authenticate the identity of a person by verifying personal characteristic Biometric device convert personal characteristic in digital code This digital code is compared with a digital code stored in the computer User access is not granted if both code do not match COMSATS University Islamabad Abbottabad Campus 71 CONT… Some of the important biometric devices are: 1. A fingerprints reader is most widely used biometric device. It scans the curve and identifications of a fingerprints 2. A facial recognition system capture the live face image of a person. It compares this image with another image stored in the computer 3. The hand geometry system is used to measure the shape and size of hand 4. A voice verification system compare the voice of the person with the stored voice 5. A Signature verification system identifies the shape of handwritten signature. Its also measure the pressure and motion used to write the signature 6. An iris recognition system read the pattern in the iris of an eye. These patterns are unique in the aye 7. Line-of-sight system are used to use your ayes to point at the screen. This technology allows some physically disable users to direct a computer. For example, a disable person can focus his eyes on specific area of the screen to issue a command to the computer. Camera is used to identify the area on which the user is focusing COMSATS University Islamabad Abbottabad Campus 72 OUTPUT DEVICES An output device is an electromechanical device that receives information from the computer and translates them in suitable form for the users. Output Device can be broadly classified into following categories: 1. Hard Copy Devices Printers Plotters 2. Soft Copy Devices Monitors Audio Output Video Output COMSATS University Islamabad Abbottabad Campus 73 PRINTERS Printer is a output device Printers prints characters, symbols and graphics on paper The printed output is called hard copy Print resolution is commonly measured in dot per inch (dpi) Printer speed measured by page per minute (ppm) or character per second (cps) The quality of printed images and text depends on printer’s resolution Printers are classified into two categories: 1. 2. impact printer non-impact printer. COMSATS University Islamabad Abbottabad Campus 74 IMPACT PRINTER Works like a typewriter The impact printers print the characters by striking them on the ribbon which is then pressed on the paper Impact printer are the oldest print technologies, which are still produced Impact printers can print a character or an entire line at a time. Are used where low-cost printing is required Dot matrix printers, daisy wheel printers and Drum/Line printers are examples of impact printers. COMSATS University Islamabad Abbottabad Campus 75 DOT MATRIX PRINTERS Dot Matrix Printers: Dot Matrix Printers print one character at a time. It produces printed images when tiny pins on a print head strike an inked ribbon When the ribbon presses against the paper, it creates dots that form characters and graphics Dot matrix printers can print alphanumeric characters, special characters, charts and graphs. They can print only in black and white. Dot matrix printers are commonly used for printing in applications like payroll and accounting. COMSATS University Islamabad Abbottabad Campus 76 DRUM PRINTER Drum Printers are line printers Fast impact printer It prints an entire line at a time It speed is measured in line per minute (lpm) Many line printers can print 3000 lines per minut COMSATS University Islamabad Abbottabad Campus 77 DAISY WHEEL PRINTER Is similar to a typewriter It uses a print wheel Print wheel is called daisy wheel. Each petal of daisy wheel contains a character A hammer strikes a petal against the ribbon when the desired character reaches the position on the paper It slower than dot matrix but better in quality COMSATS University Islamabad Abbottabad Campus 78 NON IMPACT PRINTERS Prints character and graphics on paper without striking paper The character are printed on paper with different means such as laser Some printers use spray ink while others use heat and pressure to create image Faster than impact printers More costly than impact printers They produce no noise during printing Print quality is better than non impact printers Types of non impact printers are: Laser printers Inkjet printers Thermal printers Photo printers Portable printer COMSATS University Islamabad Abbottabad Campus 79 CONT… Laser printer: Laser stand for LIGHT AMPLIFICATION BY SIMULATED EMISSION OF RADIATION Its working s similar to a photocopy machine It uses laser beams to burn special powder on the page to create a permanent image The powder is contain in the toner Print complete page at a time Laser printers process and store the entire page before printing and are also known as page printers. Print text and graphics in high quality Printing speed for home and small office is 45 pagers per minute (ppm), and for large business 150 ppm and more Their resolution ranges from 400 to 1200 dpi. COMSATS University Islamabad Abbottabad Campus 80 CONT… Inkjet printer: It print character and graphics by spraying tiny drops of liquid ink on paper Produced quality text and graphics in both black-&-white and color Price of inkjet printer is less than laser printer They are slower than laser printer Print 10 to 35 pages per minute Their resolution is more than 500 dpi. COMSATS University Islamabad Abbottabad Campus 81 CONT… Thermal printer: Produces output by melting wax-based in onto paper Not very expensive Quality is not very high It is typically used to print ATMs receipts, electronic tickets etc Some thermal printers are expensive and the quality of these printers are good, and are used in photography studios and medical labs etc COMSATS University Islamabad Abbottabad Campus 82 CONT… Photo printers: Is a colour printer designed to print high quality photographs Also called snapshot printer Some photo printer have a built in card slot The printer can print digital photo directly from a media card Some photo printers also have built-in LCD colour screen The user can view image before printing COMSATS University Islamabad Abbottabad Campus 83 CONT… Portable printer: Small Light-weight Battery-powered It can be used by mobile user to print from notebook computer, tablet or smartphone while travelling Some printer have built-in wireless port to communicate with computer Some have USB port COMSATS University Islamabad Abbottabad Campus 84 PLOTTER Produce image quality graphics in a variety of colors Are used to create maps, architectural drawing, graphics and charts Works by drawing lines on paper using pens held in a mechanical arm Plotter is a slow output device and is expensive. Plotters are of two kinds—drum plotter and flatbed plotter. COMSATS University Islamabad Abbottabad Campus 85 CONT… Flatbed plotter: Used to plot or draw images Contain pens for drawing The paper is placed on table-like surface Software instruct the pens to move down on the paper The pen then moves on the paper for creating image Drum printer: Uses a rotating drum or cylinder The desired pens are mounted on the drum The pens moved to the left and right as the drum rotate The movement create the desired image The length of the plot is almost is unlimited Width of the image depends on width of drum COMSATS University Islamabad Abbottabad Campus 86 SOFT COPY OUTPUT DEVICES Following are the softcopy output devices: Monitors Audio Output Video Output Monitors Monitor is a common output device. The monitor is provided along with the computer, to view the displayed output. A monitor is of two kinds - monochrome display monitor and color display monitor. A monochrome display monitor uses only one color to display text and color display monitor can display 256 colors at one time. An image on the monitor is created by a configuration of dots, also known as pixels. COMSATS University Islamabad Abbottabad Campus 87 CONT… The clarity of image on the computer screen depends on three factors Resolution of Screen :The number of pixels in horizontal and vertical direction. Dot Pitch: The number of pixels in horizontal and vertical direction. Refresh Rate : The number of times per second the pixels are recharged so that their glow remains bright. Two basic types of monitors used today are cathode-ray-tube (CRT) and LCD (Liquid Crystal Display) .flat-panel. 1. Cathode-Ray Tube CRT Monitor : The CRT display is made up of small picture elements called pixels. The smaller the pixels, the better the image clarity, or resolution Large in Size High power consumption COMSATS University Islamabad Abbottabad Campus 88 CONT… 2. Flat-Panel Display Monitor The flat-panel display refers to a class of video devices that have reduced volume, weight and power requirement in comparison to the CRT You can hang them on walls Current uses of flat-panel displays include calculators, video games, monitors, laptop computer, graphics display LCD (Liquid Crystal Display), LED and Plasma are types of flat panel display which uses liquid crystals in its primary form of operation. COMSATS University Islamabad Abbottabad Campus 89 AUDIO OUTPUT DEVICES A complete sound system consists of sound card, microphone, speaker and the appropriate software. Audio response provides audio output from the computer. Audio output device like speakers, headset or headphone is used for audio output sound from computer. Speakers: Is the most common device of audio output device It connect to the sound card in the system and provide audio output for computer Wireless speaker also available to play audio COMSATS University Islamabad Abbottabad Campus 90 CONT… Headphones & headset: Headphones can be used to instead to speakers, so that other people are not disturbed Headphones are placed outside the ear Headset is a headphone with a built-in microphone It is often used when making telephone calls Wireless headset commonly used with mobile phone COMSATS University Islamabad Abbottabad Campus 91 VIDEO OUTPUT DEVICES Typical examples of video output devices are monitors and projectors (video) Data projector: Data projector is an output device Project the output of the computer screen onto a large screen The output projected by the data projector can be viewed by a number of peoples very clearly Used in classes to deliver lectures to many students Type of data projects LCD projector DLP projector COMSATS University Islamabad Abbottabad Campus 92 CONT… LCD projector: Stands for liquid crystal display Attached directly to computer Uses its own light source to display information shown on the computer screen DLP Projector: Stands for digital light processing Use tiny mirrors to reflect light Produce brighter and sharper image than LCD COMSATS University Islamabad Abbottabad Campus 93 THANKS COMSATS University Islamabad Abbottabad Campus 94
