Chapter 6 Input and Output

chapter 6- Input and Output What Is Input? Input is any data or instructions that are used by a computer. They can come directly from you or from other sources. You provide input whenever you use system or application programs. Input devices are hardware used to translate words, numbers, sounds, images, and gestures that people understand into a form that the system unit can process. One of the most common ways to input data is by a keyboard. Most keyboards use an arrangement of keys given the name QWERTY. QWERTY : This name reflects the keyboard layout by taking the letters of the first six alphabetic characters found on the top row of keys displaying letters. Keyboards keyboard designs:four basic categories of keyboards: 1) Traditional keyboards—  These full-size keyboards are widely used on desktops and larger computers.  The standard U.S. traditional keyboard has 101 keys.  Traditional keyboards provide function keys, navigation keys, and a numeric keypad.  Caps Lock key, are toggle keys: These keys turn a feature on or off. Others, such as the Ctrl key, are combination keys :which perform an action when held down in combination with another key. 2) Laptop keyboards—  these keyboards are smaller than traditional keyboards and are widely used on laptop computers.  laptop keyboards typically have fewer keys, do not include a numeric keypad, and do not have a standard location for the function and navigation keys. 3) Virtual keyboards—  These keyboards are used primarily with mobile devices and tablets.  The keys are typically displayed on a screen and selected by touching their image on the screen. 4) Thumb keyboards—  These keyboards are used on smartphones and other small mobile devices.  Designed primarily for communicating via texting and connecting to the web.  These keyboards are very small. 32 Pointing Devices provide an intuitive interface with the system unit by accepting physical movements or gestures such as a finger pointing or moving across a screen and converting these movements into machinereadable input. There are a wide variety of pointing devices, including: I. II. III. IV. Mouse :  A mouse controls a pointer that is displayed on the monitor.  The mouse pointer usually appears in the shape of an arrow( changing depending on application).  Optical mouse is the most widely used.  A cordless or wireless mouse uses radio waves or infrared light waves.  A touch pad operates by touching or tapping a surface, It is widely used instead of a mouse with laptops and some types of mobile devices. Touch screen :  A touch screen allows users to select actions or commands by touching the screen with a finger or penlike device.  Multitouch screens can be touched with more than one finger, it allows for rotating graphical objects or zooming in and out .  Multitouch screens are commonly used with tablets and smartphones, as well as some laptop computers and desktop monitors. Game Controllers: devices that provide input to computer games. The four most popular and specialized game controllers are: • Jo sti ks control game actions by users varying the pressure, speed, and direction of a control stick. • Ga i g i e high precision, fast responsiveness, programmable buttons, and better ergonomics. • Ga epads held by two hands and provide a wide array of inputs including motion, turning, stopping, and firing. • Motio -sensing devices control games by user movements. Stylus  is a penlike device typically used with tablets and mobile devices.  Handwriting recognition software translates handwritten notes into a form that the system unit can process. Scanning Devices convert scanned text and images into a form that the system unit can process. There are five types of scanning devices: 1. Optical Scanners (scanner), accepts documents consisting of text and/or images and converts them to machine-readable form.  These devices do not recognize individual letters or images. Rather, they recognize light, dark, and colored areas that make up individual letters or images.  powerful tools for end users, including graphics and advertising professionals who scan images and combine them with text. 33 There are four basic types of optical scanners: a. Flatbed scanner is much like a copy machine. The image to be scanned is placed on a glass surface, and the scanner records the image. b. Document scanner quickly scan multipage documents. It automatically feeds one page of a document at a time through a scanning surface. c. Portable scanner a handheld device that slides across the image, making direct contact. d. 3D scanners use lasers, cameras, or robotic arms to record the shape of an object. /cannot recognize light, dark, and colored areas. 2. Card Readers interpret the encoded information. the most common type is the magnetic card reader.  smart cards, includes additional security in the form of a microchip embedded in the credit card. This chip contains encrypted data that makes it nearly impossible for criminals to forge a duplicate card. 3. Bar Code Readers either handheld wand readers or platform scanners. They contain photoelectric cells that scan or read bar codes, or the vertical zebra-striped marks printed on product containers./Smartphones also scan codes. There are a variety of different codes including : • UPCs U i e sal P odu t Codes used etail sto es to auto ate the p o esses to he k out customers, to change product prices, and to maintain inventory records. • Ma iCode used the U ited Pa el Se i e UPS a d others to automate the process of routing packages, tracking in-transit packages, and locating lost packages. 4. RFID Readers : RFID(radio-frequency identification) tags are tiny chips that can be embedded in most everything. These chips contain electronically stored information that can be read using an RFID reader located several yards away. They are widely used to 1-track and locate lost pets; 2-to monitor production and update inventory; 3- to record prices, product descriptions, and locations of retail items. 5. Character and Mark Recognition Devices are scanners that are able to recognize special characters and marks. Three types are : • Mag eti -ink character recognition (MICR)—used by banks to automatically read those unusual numbers on the bottom of checks and deposit slips. A special-purpose machine known as a reader/sorter reads these numbers and provides input that allows banks to efficiently maintain customer account balances. • Opti al-character recognition (OCR)—uses special preprinted characters that can be read by a light source and changed into machine-readable code. A common OCR device is the handheld wand reader. (See Figure 6-12.) These are used in department stores to read retail price tags by reflecting light on the printed characters. • Opti al-mark recognition (OMR)—senses the presence or absence of a mark, such as a pencil mark. OMR is often used to score standardized multiple-choice tests. 34 Image Capturing   Devices Optical scanners, like traditional copy machines, can make a copy from an original. Image capturing devices, create or capture original images. These devices include digital cameras and webcams. A. Digital Cameras capture images digitally /store the images on a memory / able to record video as well. All tablets and smartphones have built-in digital cameras. B. Webcams Digital video cameras capture images and send them to a computer for broadcast over the Internet./ Webcams are built into most smartphones and tablets. Audio-Input Devices convert sounds into a form that can be processed by the system unit. Audio input can take many forms, including the human voice and music. Voice Recognition Systems use a microphone, a sound card, and special software. These systems allow users to create documents using voice commands.  Apple phones come with Siri, Windows phones come with Cortana, and Google phones come with Google Now.  Some systems are even able to translate dictation from one language to another, such as from English to Japanese. What Is Output? Output is processed data or information. Output typically takes the form of text, graphics, photos, audio, and/or video. Output devices: are any hardware used to provide or to create output. They translate information that has been processed by the system unit into a form that humans can understand. The most widely used OUTPUTES are : i. Monitors : Also known as display screens, monitors present visual images of text and graphics. The output is often referred to as soft copy. Monitors vary in size, shape 35 Basic Features : The most important characteristic of a monitor is its clarity ( the quality and sharpness of the displayed images.) It is a function of several monitor features, including resolution, dot pitch, contrast ratio, size, and aspect ratio.  Resolution. Resolution is expressed as a matrix of these dots or pixels(series of dots or pixels forms images) .  The highe a o ito ’s esolutio the o e pi els , the lea e the i age produced.  Dot (pixel) pitch is the distance between each pixel.  The lower the dot pitch (the shorter the distance between pixels), the clearer the images produced.  Contrast ratios i di ate a o ito ’s a ilit to displa i ages. It o pa es the light i te sit of the brightest white to the darkest black.  The higher the ratio, the better the monitor. Good monitors typically have contrast ratios between 500:1 and 2000:1.  Size, o a ti e displa a ea, is easu ed the diago al le gth of a o ito ’s ie i g a ea. Common sizes are 15, 17, 19, 21, and 24 inches.  Aspect ratio indicates the proportio al elatio ship et ee a displa ’s idth a d height. This relationship is expressed by two numbers separated by a colon (:). Another importatnt feature is the ability to accept touch or gesture input such as finger movements including swiping, sliding, and pinching. Flat-Panel Monitors Flat-panel monitors are the most widely used type of monitor today. They are thinner, are more portable, and require less power to operate. Almost all flat-panel displays are backlit (meaning that a common source of light is dispersed over all the pixels on the screen.) There are three basic types of flat-panel monitors: LCD, LED, and OLED. • LCD li uid stal displa olde o ito s a d is t pi all less e pe si e. • LED (light-emitting diode) / most new monitor/use similar technology with a more advanced backlighting technology. Better-quality images, are slimmer, and are more environmentally friendly( as they require less power and use fewer toxic chemicals to manufacture. ) • OLED o ga i light-emitting diode) /monitors use a thin layer of organic compound that produces light. By eliminating the backlight, /even thinner with better power efficiency and contrast ratios. 36  Curved Monitors It has a concave screen that provides better viewing angles near the edges of the screen. used for high-end televisions and for gamers searching for a highly immersive viewing experience. E-book Readers (electronic books) Are traditional printed books in electronic format. These books are available from numerous sources including many public and private libraries, bookstore websites, and the cloud. - dedicated mobile devices for storing and displaying e-books and other electronic media / use a technology known as e-ink. - Two well-known e- ook eade s a e A azo ’s Ki dle a d Ba es & No le’s Nook Si ple Tou h. • Digital or i tera ti e hite oards are specialized devices with a large display connected to a computer or projector. Digital whiteboards are widely used in classrooms and corporate boardrooms. • Ultra-high-definition television (UHDTV) delivers a much clearer and more detailed wide-screen picture than regular HDTV. One of the most recent and dramatic advances is 3D UHDTV. Using special viewing glasses, 3D UHDTV provides theater-quality three-dimensional viewing. • Digital proje tors project the images from a traditional monitor onto a screen or wall. Projected images can be difficult to see in bright rooms, so they are best used in dark rooms with curtains or no windows. Printer Printers translate information that has been processed by the system unit and present the information on paper. Printer output is often called hard copy. Features a. Resolution similar to monitor resolution. It is a measure of the clarity of images produced. Printer resolution, however, is measured in dpi (dots per inch).  The higher the dpi, the better the quality of images produced. b. Color capability it is more expensive to print in color, most users select black ink .The most common black ink selection is grayscale.  Color is used more selectively for final reports containing graphics and for photographs. c. Speed is measured in the number of pages printed per minute. d. Memory within a printer is used to store printing instructions and documents waiting to be printed. The more memory, the faster it will be able to print large documents. e. Duplex printing allo s auto ati p i ti g o oth sides of a sheet of pape . It’s ot currently a standard feature for all printers 37 Inkjet Printers Inkjet printers spray ink at high speed onto the surface of paper. This process produces high-quality images in a variety of colors, making it ideal for printing photos. - relatively inexpensive and are the most widely used printers. In addition, they are reliable and quiet. The most costly aspect of inkjet printers is replacing the ink cartridges.  Typical inkjet printers produce 15 to 19 pages per minute of black-only output and 13 to 15 pages of color output. Laser Printers use a laser light beam to produce images with excellent letter and graphics quality. More expensive / faster and are used in applications requiring high-quality output. There are two categories of laser printers: Personal laser printers are less expensive and are used by a single user. They typically can print 15 to 17 pages a minute. Shared laser printers typically support color, are more expensive, and are used (shared) by a group of users. Shared laser printers typically print over 50 pages a minute. 3D Printers 3D printers, also known as additive manufacturing, create three-dimensional shapes by adding very thin layer after layer of material until the final shape is fully formed. Other Printers • Cloud pri ters are printers connected to the Internet that provide printing services to others on the Internet. Google Cloud Print is a service that supports cloud printing. • Thermal printers use heat elements to produce images on heat-sensitive paper. These printers are widely used with ATMs and gasoline pumps to print receipts. • Plotters are special-purpose printers for producing a wide range of specialized output. Using output from graphics tablets and other graphical input devices, plotters create maps, images, and architectural and engineering drawings.  Plotters are typically used by graphic artists, engineers, and architects to print out designs, sketches, and drawings. 38 Audio-Output Devices translate audio information from the computer into sounds that people can understand. The most widely used audio-output devices are speakers and headphones. These devices connect to a sound card within the system unit. The sound card is used to capture as well as play back recorded sounds. Audio-output devices are used to play music, vocalize translations from one language to another, and communicate information from the computer system to users. Usage : It is used with many smartphones, cars, and soft drink machines. It is used as a reinforcement tool for learning, such as to help students study a foreign language. It also is used in many supermarkets at the checkout counter to confirm purchases. One of its most powerful capabilities is to assist the physically challenged. Combination Input and Output Devices Common combination devices include headsets, multifunctional devices, telephones, drones, robots, and virtual reality headgear and gloves. Headsets : combine the functionality of microphones and headphones. The microphone accepts audible input and headphones provide audio output. Headsets are an integral part of serious video game systems. Multifunctional Devices (MFD) typically combine the capabilities of a scanner, printer, fax, and copy machine. They cost about the same as a good printer or copy machine but require much less space than the single-function devices they replace. Their disadvantages are lower quality and unreliability. The output quality for any one function is often not quite as good as that of the separate single-purpose devices. The reliability of multifunctional devices suffers because problems with one of the functional parts can make the entire device inoperable. Telephones are input and output devices for receiving and sending voice communication. Voice over IP (VoIP) is a set of standards or technologies that support voice and other types of communication over the Internet. Telephony, is the VoIP application that uses Internet rather than traditional telephone lines to support voice communication.  Examples of VOIP services that available for free: Skype from Microsoft, Hangouts from Google, and FaceTime from Apple. Drones, or unmanned aerial vehicles (UAV), Most drones take input from a controller .The drones act as an output device, sending back video and sound to the user. 39 Robots use cameras, microphones, and other sensors as inputs. Based on these inputs, robotic outputs can be as complex as exploring damaged nuclear reactors to as simple as taking a photo. Robots can be found almost everywhere . Virtual Reality Headgear and Gloves Virtual reality (VR) is an artificial, or simulated, reality created in 3D by computers. It strives to create a virtual or immersive experience by using specialized hardware that includes headgear and gloves.The headgear has earphones and three-dimensional stereoscopic screens. The gloves have sensors that collect data about your hand movements. Ergonomics is defined as the study of human factors related to things people use.. For computer users and manufacturers this means designing input and output devices to increase ease of use and to avoid health risks. Recommendations to avoid physical discomfort are :   Taking frequent rest breaks and by using well-designed computer furniture Eyestrain and headache: To make the computer easier on the eyes, take a 15-minute break e e hou o t o. Keep e e thi g ou’ e fo usi g o at a out the same distance. Clean the screen of dust from time to time.  Back and neck pain: Make sure your equipment is adjustable. You should be able to adjust your chair for height and angle, and the chair should have good back support. The monitor should be at eye level or slightly below eye level. Use a footrest, if necessary, to reduce leg fatigue.  Repetitive strain injury: (RSI) is any injury that is caused by fast, repetitive work that can generate neck, wrist, hand, and arm pain. Ergonomically correct keyboards have been developed to help prevent injury from heavy computer use. (See Figure 6-32.) In addition to using ergonomic keyboards, you should take frequent short rest breaks and gently massage your hands. Portable Computers The design of portable computers including presents some specific ergonomic challenges. • Laptops do not allow correct positioning of keyboard and screen; raise level of laptop and use external keyboard. • Tablets ith i tual ke oa ds ause i p ope alig e t of use ’s head; take frequent breaks, move while working, use cover or stand, use external keyboard. • S a tpho es require extensive use of thumbs; keep wrists straight, head up, and shoulders straight and use other fingers. 40