Using Information Technology Chapter 5 Hardware--Input & Output To the instructor: This presentation attempts to cover every term in the text, sometimes via a slide, sometimes via the Notes page. Additional material beyond what is in the text is presented via: Occasional “FACTOID” notations on the Notes page, and; Occasional hyperlinks in the slides themselves. ScreenTip text has been added to each hyperlink allowing you to see in advance of selecting the hyperlink where that link will take you. In addition, the last ~20 slides are questions covering the material just presented. They can be used to increase interaction between the instructor and students at the end of each lecture, to ensure students understand the material just presented, etc. Finally, some of the Notes pages include “Discussion questions” for use in encouraging student interaction during the lecture.

Hardware--Input & Output Taking Charge of Computing & Communications 5.2 Input Hardware 5.3 Output Hardware Key Questions (from the text): 5.1 Input & Output. How is input and output hardware used by a computer system? 5.2 Input Hardware. What are the three categories of input hardware, what devices do they include, and what are their features? 5.3 Output Hardware. What are the two categories of output hardware, what devices do they include, and what are their features?

5.1 Input & Output Input hardware - devices that translate data into a form the computer can process Output hardware - devices that translate information processed by the computer into a form that humans can understand

5.2 Input Hardware Keyboard - a device that converts letters, numbers, and other characters into electrical signals that can be read by the computer’s processor Traditional keyboards… Braille keyboard Traditional keyboards include Braille and one-handed keyboards for the physically challenged, plus left-handed keyboards for the 10% of the population that is left-handed, and many others. One-handed keyboard

Keyboards Specialty keyboards and terminals: Dumb terminal, VDT, display & keyboard, but no processing Intelligent terminal Internet terminal Dumb terminal - a display screen and a keyboard, which can input and output but not process data. Also called a video display terminal (VDT). The picture depicts dumb terminals used by airline reservations clerks. Dumb terminal

Keyboards Specialty keyboards and terminals: Examples of intelligent terminals: Automatic teller machine (ATM) Point-of-sale (POS) terminal Specialty keyboards and terminals: Dumb terminal Intelligent terminal Has own memory & processor Internet terminal Intelligent terminal - has its own memory and processor, as well as a display screen and keyboard. FACTOID: Some sources distinguish between an intelligent terminal and a merely smart terminal. The latter does not have as many processing capabilities as an intelligent terminal.

PDA (Internet terminal) Keyboards Specialty keyboards and terminals: Dumb terminal Intelligent terminal Internet terminal: Web terminal Network computer Online game player PC/TV PDA Internet terminal - provides access to the Internet. Types of Internet terminals: Web terminal - displays Web pages on a TV set. Network computer - a cheap, stripped-down computer that connects people to networks. Online game player - allows users to play games and connect to the Internet. PC/TV - merges the PC with the TV. Personal digital assistant (PDA) - a handheld computer that can do two-way wireless messaging. PDA (Internet terminal)

Mouse for right-handed user Pointing Devices Pointing devices - control the position of the cursor or pointer on the screen Mouse Trackball Pointing stick Touchpad Discussion question: Why is the mouse pictured described as one “for right-handed user?” Answer: The left button, to be used with a right-handed person’s index finger, is larger than the right button, because it is expected that this button will be used more often, and a larger button is easier to select. By contrast, a left-handed person’s index finger would need the right button to be larger than the left (or at least equal size!). Mouse for right-handed user

Pointing Devices The mouse and its variants: Mouse Trackball Pointing stick Touchpad Touch pad Trackball - a movable ball, mounted on top of a stationary device that can be rotated using fingers or palm. Discussion question: Why is the trackball pictured described as “ergonomic?” Hint: Why is the trackball pictured intended for right-handed users? Answer: Because the stationary device that holds the trackball is molded to fit the contours of a right hand. Ergonomic trackball Pointing stick

Pointing Devices Touch screen - a video display screen that has been sensitized to receive input from the touch of a finger Touch screen

Pointing Devices Pen input: Pen-based computer system - allows users to enter handwriting and marks onto a computer screen by means of a penlike stylus rather than by typing on a keyboard Light pen - a light-sensitive penlike device connected by a wire to the computer terminal

Pointing Devices Pen input: Digitizer - converts drawings and photos to digital data using a mouselike device called a puck Digitizing tablet - electronic plastic board on which each specific location corresponds to a location on the screen Digitizing tablet

Source Data-Entry Devices Scanning devices - imaging systems: Scanners - devices that use light-sensing equipment to translate images of text, drawings, photos, and the like into digital form Source data-entry devices - create machine-readable data on magnetic media or paper or feed it directly into the computer’s processor. Imaging system (or image scanner or graphics scanner) - device which converts text, drawings, and photographs into digital form that can be stored in a computer system and then manipulated, output, or sent via modem to another computer. Electronic imaging - the software-controlled integration of separate images, using scanners, digital cameras, and advanced graphic computers.

Source Data-Entry Devices Scanning devices – bar-code readers: Bar codes - vertical zebra-striped marks you see on most manufactured retail products Bar-code readers - optical scanners that translate the symbols in the bar code into digital code

Source Data-Entry Devices Scanning devices - mark- & character-recognition: MICR - Magnetic-ink character recognition. Reads the strange-looking numbers printed at the bottom of checks OMR OCR

Source Data-Entry Devices Scanning devices - mark- & character-recognition: MICR OMR - Optical mark recognition. Uses a device that reads pencil marks and converts them into computer-usable form OCR

Source Data-Entry Devices Scanning devices:mark- & character-recognition: MICR OMR OCR - Optical character recognition. Uses a device that reads preprinted characters in a particular font and converts them to digital code

Source Data-Entry Devices Scanning devices - fax machines… Types of fax machines: Dedicated fax machine Fax modem Dedicated fax machine Fax machine - scans an image and sends it as electronic signals over telephone lines to a receiving fax machine, which prints out the image on paper. Also called facsimile transmission machine. Dedicated fax machine - specialized device that does nothing except send and receive fax documents. Fax modem

Other Source Data-Entry Devices Audio-input devices Webcams and video-input cards Digital cameras Voice-recognition systems Webcam - a camera that attaches to a computer to record moving images that can then be posted on a website in real time. Video-capture card - a special digitizing card that converts the analog signals that come from a VCR or a camcorder into digital form.

Other Source Data-Entry Devices Audio-input devices Webcams and video-input cards Digital cameras Voice-recognition systems Human-biology input devices (biometrics) Digital camera - uses a light-sensitive processor chip to capture photographic images in digital form on a small diskette inserted in the camera or on flash-memory chips.

5.3 Output Hardware Softcopy - data that is shown on a display screen or is in audio or voice form Hardcopy - printed output

Softcopy Output: Display Screens Display screens - output devices that show programming instructions and data as they are being input and information after it is processed

Softcopy Output: Display Screens Screen clarity… Pixel (picture element) - the smallest unit on the screen that can be turned on and off or made different shades

Softcopy Output: Display Screens Screen clarity… Dot pitch (dp) - the amount of space between the centers of adjacent pixels; the closer the dots, the crisper the image

Softcopy Output: Display Screens Standard resolutions (horizontal x vertical) 640 x 480 800 x 600 1024 x 768 1280 x 1024 1600 x 1200 1920 x 1440 Screen clarity… Resolution - the image sharpness of a display screen; the more pixels there are per square inch, the finer the level of detail dpi = dots per inch

Softcopy Output: Display Screens Screen clarity… Refresh rate - the number of times per second that the pixels are recharged so that their glow remains bright The higher the refresh rate, the more solid the image looks (less flicker).

Softcopy Output: Display Screens Two types of monitors: CRT - a vacuum tube used as a display screen in a computer or video display terminal Flat-panel display - made up of two plates of glass separated by a layer of a substance in which light is manipulated CRT stands for Cathode Ray Tube, and is used in television sets in addition to monitors.

Softcopy Output: Display Screens Active-matrix versus passive-matrix flat-panel displays: Active-matrix - each pixel on the screen is controlled by its own transistor (brighter & sharper, but more expensive) Passive-matrix - a transistor controls a whole row or column of pixels (provides sharper image for single color screens but more subdued for color) Active-matrix display advantages: Brighter Sharper Do not leave “ghosts” when the display changes quickly Passive-matrix display advantages: Cheaper Use less power

Softcopy Output: Display Screens Color & resolution standards: SVGA – Super video graphics array (most common w/ 15” monitors) XGA – Extended graphics array (17-19” monitors) SXGA – Super extended graphics array (19”-21” monitors) UXGA - Ultra extended graphics array (popular w/ design & graphic artists SVGA (Super Video Graphics Array) XGA (Extended Graphics Array) SXGA (Super Extended Graphics Array) UXGA (Ultra Extended Graphics Array)

Hardcopy Output: Printers Printer - an output device that prints characters, symbols, and perhaps graphics on paper or another hardcopy medium Dpi (dots per inch) - resolution measure for printers. Specifies the number of dots that are printed in a linear inch

Hardcopy Output: Printers Impact printer - forms characters or images by striking a mechanism such as a print hammer or wheel against an inked ribbon, leaving an image on paper (dot matrix printer) Non-impact printer - forms characters and images without direct physical contact between the printing mechanism and paper Laser printer - creates images on a drum which are treated with a magnetically charged toner, & then transferred from drum to paper Ink-jet printers - spray small, electrically charged droplets of ink from four nozzles through holes in a matrix at high speed onto paper Thermal printers - use colored waxes and heat to produce high quality images by burning dots onto special paper Dot-matrix printer - contains a print head of small pins, which strike an inked ribbon against paper to form characters or images. Advantage of dot-matrix printer: Can be used to print multi-part forms Disadvantage of dot-matrix printer: Noisy!

Hardcopy Output: Printers Multifunction printer - output device that combines several capabilities, such as printing, scanning, copying, and faxing

Other Output Sound output - devices which produce digitized sounds, ranging from beeps and chirps to music Voice output - devices which convert digital data into speech-like sounds Video output - photographic images which are played at 15-29 frames per second to give the appearance of full motion Videoconferencing - another form of video output, in which people in different geographical locations can have a meeting--can see and hear one another--using computers and communications.

Concept Check Which type of scanning technology reads the special characters printed at the bottom of checks? Magnetic-ink character recognition (MICR)

Concept Check What is the smallest unit on the screen that can be turned on and off or made different shades? Pixel (short for picture element)

Concept Check What is the measure specifying the number of times per second that screen pixels are recharged? Refresh rate

Concept Check How is screen resolution specified--vertical x horizontal, or horizontal x vertical? Horizontal x vertical

Concept Check What is the measure of resolution for printers? Dots per inch (dpi)

Concept Check What is the amount of space between the centers of adjacent pixels? Dot pitch (dp)

Concept Check What type of scanning technology is used to read pencil marks, such as those made by students on examination forms? OMR (Optical mark recognition)

Concept Check What is an example of an impact printer? Dot-matrix printer

Concept Check Which type of printer produces the very highest-quality color output? Thermal printer

Concept Check What type of input device consists of a small, flat surface over which you slide your finger, using the same movements as you would with a mouse? Touchpad

Concept Check What is the term for printed output? Hardcopy

Concept Check Does a very crisp image require a small dot pitch or a large dot pitch? A small dot pitch (the closer the dots, the crisper the image)