Embed Size (px)
Citation preview
Using Information Technology
Lecture 3Hardware--Input & Output
Hardware--Input & Output Taking Charge of Computing & Communications
3.1 Input & Output
3.2 Input Hardware
3.3 Output Hardware
3.4 The Future of Input & Output
6.1 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
6.2 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…
Keyboards
Specialty keyboards and terminals:
Dumb terminalIntelligent terminalInternet terminal
Pointing Devices
Pointing devices - control the position of the cursor or pointer on the screen
Mouse TrackballPointing stickTouchpad
Pointing Devices
Touch screen - a video display screen that has been sensitized to receive input from the touch of a finger
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
Pointing Devices
Pen input:
Light pen - a light-sensitive penlike device connected by a wire to the computer terminal
Pointing DevicesPen 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
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
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- and character-recognition:
MICR - Magnetic-ink character recognition. Reads the strange-looking numbers printed at the bottom of checks
OMR - Optical mark recognition. Uses a device that reads pencil marks and converts them into computer-usable form
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
Source Data-Entry Devices
Scanning devices - fax machines…
Types of fax machines:
Fax modem
Other Source Data-Entry Devices
Audio-input devices Record analog sound and translate it for digital storage and processing
Require either an audio board or a MIDI board
Other Source Data-Entry Devices
Webcams and video-input cards
Other Source Data-Entry Devices
Digital cameras
Other Source Data-Entry Devices
Voice-recognition systems
More Source Data-Entry Devices
Sensors
More Source Data-Entry Devices
Radio-frequency identification
6.3 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
Screen clarity…
Resolution - the image sharpness of a display screen; the more pixels there are per square inch, the finer the level of detail
Standard resolutions(horizontal x vertical)
640 x 480800 x 6001024 x 7681280 x 10241600 x 12001920 x 1440
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
Softcopy Output: Display Screens
Two types of monitors:
Flat-panel display - made up of two plates of glass separated by a layer of a substance in which light is manipulated
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
Passive-matrix - a transistor controls a whole row or column of pixels
Softcopy Output: Display Screens
Color & resolution standards:
SVGA
XGA
SXGA
UXGA
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
Non-impact printer - forms characters and images without direct physical contact between the printing mechanism and paper
Hardcopy Output: Printers
Nonimpact printers:
Laser printer - creates images on a drum which are treated with a magnetically charged toner, and then transferred from drum to paper
Replacing a laser toner cartridge
Hardcopy Output: Printers
Nonimpact printers:
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 images by burning dots onto special paper
Hardcopy Output: Printers
Plotter - a specialized output device designed to produce high-quality graphics in a variety of colors
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
6.4 The Future of Input & Output
More input devices in remote locations
More refinements in source data automation
More output in remote locations
Increasingly realistic--even lifelike--forms of output
Toward More Source Data Automation
More refinements in source data automation:
High-capacity bar codes3-D scannersMore sophisticated touch devicesSmarter smart cardsMore sensors
Toward More Source Data Automation
More refinements in source data automation:
Better voice recognition
Smaller electronic cameras
Pattern-recognition & biometric devices
Brainwave devices
Toward More Output in Remote Locations
Electronic news tablet - a textbook-sized device for downloading a newspaper and then carrying around to read
Toward More Realistic Output
Display screens--better and cheaper
Audio--higher fidelity
Video--movie quality for PC’s
Three-dimensional display
