Input and Output:(HARDWARE)
Chapter 1
Input and Output
Input
• Users submit input data
Output
• Users get processed information
Input
• Data from the user to the computer
• Converts raw data into electronic form
Keyboard
• Traditional– Looks like typewriter
with extra keys
• Non-traditional– Fast food restaurants– Each key represents a
food item rather than a character
Keyboard
Function Keys
• Give commands
• Software specific
Main Keyboard
• Typewriter keys
• Special command keys
Keyboard
• Numeric Keys– Num Lock – toggle – On – numeric data & math symbols– Off – cursor movement
• Cursor Movement Keys
KeyboardSpecial Keys
Enter
Esc
Alt
Ctrl
Caps Lock
Shortcut
Windows
Shift
Pointing Devices
• Position a pointer / cursor on the screen
• Controls drawing instruments in graphics applications
• Communicate commands to a program
Pointing Devices Mouse
• Types– Mechanical– Optical– Wireless
• Features– Palm-sized– 1 or 2 buttons– Wheel
Other Pointing Devices
• Trackball– Upside-down mouse– Ball on top– Roll ball with hand– Laptop computers
• Touchpad– Pressure-sensitive pad– Cursor moves as you
slide your finger– Laptop computers
Other Pointing Devices
Pointing stick• Pressure-sensitive post• Mounted between G and H keys on keyboard• Apply pressure in a direction to move cursor
Joystick• Short lever• Handgrip• Distance and speed of movement control pointer
position
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Graphics Tablet
• Digitizing tablet
• Rectangular board
• Invisible grid of electronic dots
• Write with stylus or puck
• Sends locations of electronic dots as stylus moves over them
• Creates precise drawings
• Architects and engineers
Touch Screens
• Human points to a selection on the screen
• Types– Edges emit horizontal and vertical beams
of light that crisscross the screen– Senses finger pressure– Light pen for pointing
Touch Screens
• Kiosks– Self-help stations– Easy to use
– Where found• Malls• Disney World• Government offices
Pen-based Computing
• Small hand-held devices
• Electronic pen (stylus)– Pointer– Handwritten input
• Personal Digital Assistants (PDA)
Source Data Automation
• Special equipment to collect data at the source
• Sent directly to a computer
• Avoids need to key data
• Related input areas– Magnetic-Ink Character Recognition– Scanners– Optical recognition devices– Voice
MICRMagnetic-Ink Character Recognition
• Read characters made of magnetic particles
• Numbers on the bottom of checks
• MICR inscriber – adds characters to check that show amount cashed
Optical Scanners
• Optical recognition
• Light beam scans input data
• Most common type of source input
• Document imaging – converts paper documents to electronic form
• Converts snapshots into images
• Converts scanned picture into characters – OCR
Exact computer-produced replica of originalExact computer-produced replica of original
Types of Scanners
• Flatbed– One sheet at a time– Scans bound documents
• Sheetfeed– Motorized rollers– Sheet moves across
scanning head– Small, convenient size– Less versatile than flatbed– Prone to errors
Types of Scanners
• Handheld– Least expensive– Least accurate– Portable– User must move the scanner in a straight
line at a fixed rate– Wide document causes problems
Optical Recognition
• Optical mark recognition (OMR)– Mark sensing– Exams– Recognizes the location of the
marks
• Optical character recognition (OCR)– Light source reads special
characters– OCR-A is ANSI standard typeface
for optical characters
Optical Recognition Wand Reader
Retail stores
Libraries
Hospitals
Factories
Optical RecognitionBar Code Reader
• Photoelectric device
• Reads bar codes
• Inexpensive
• Reliable
• Where Used?– Supermarket – UPC– Federal Express
Optical RecognitionHandwritten Characters
Must follow rigid rules
• Size
• Completeness
• Legibility
Voice Input
• Speech Recognition
• Speech recognition devices– Input via a microphone– Voice converted to binary code
• Problems– Speaker-dependent– Voice training
Voice Input
• Changing radio frequencies in airplane cockpits
• Placing a call on a car phone
• Requesting stock-market quotations over the phone
• Command from physically disabled users
Voice Input
• Discrete work systems– Understand isolated words– Pause between words– Difficult for dictation
• Continuous work systems– Normal speaking pattern– Easy to use– Faster and easier to dictate than to key
Digital Cameras
• Photos stored in electronic form
• No film
• Point and shoot
• Edit
Output
• Information for the user
• Types– Screen – soft copy– Printer – hard copy– Voice– Sound– Graphics
Monitor
• Data that is entered appears on the screen
• Screen is part of the monitor
Monitor
Cathode Ray Tube (CRT)
Flat panel displayLiquid Crystal Display (LCD)
Flat-panel Screens
• Liquid Crystal Display (LCD)
• Primarily on laptops
• Moving to desktop
• Skinny (depth) regardless of size
Flat-panel Screens
• Crisp, brilliant images
• Easy on eyes
• No flicker
• Full dimension is useable
• More expensive that CRT monitors
Printer
• Produces information on paper
• Orientation– Portrait– Landscape
• Methods of printing– Impact– Nonimpact
Impact Printers
Line printer
One line at a time
High volume
Low quality
Dot-matrix printer
One character at a time
Nonimpact PrinterLaser Printer
Nonimpact PrinterLaser Printer
• Transfers images to paper using a light beam
• Prints one page at a time
• 600-1200 dpi – High quality
• Speed– Personal laser printers: 8-10 ppm– Network laser printers: 35-50 ppm– High-volume laser printers: up to 1000 ppm
• Black and white / color
Nonimpact PrinterInk-jet Printer
• Spray ink at paper
• Black and white / color
• Excellent graphics
• Good quality
• Slower than laser
Nonimpact Printer
Choose based upon:
• Speed
• Quality
• Black and white vs. color
• Price
Sound
Creates multimedia outputMultiple sight and sound effects
SpeakersSound card
Voice OutputSpeech Synthesis
• Enables machines to talk to people
• Types– Voice synthesizers– Voice output devices– Audio-response units
• Convert data in storage to vocalized sounds
• Synthesis by analysis – human sounds are stored and reproduced as needed
• Synthesis by rule – creates artificial speech
Voice OutputSpeech synthesis
Uses
• Automobiles
• Telephone surveys
• Catalog order is ready
• Your payment is late reminder
Music and Other Sounds
• MIDI (Musical Instrument Digital Interface)– Communicates between MIDI devices and
computer– Rules that produce and process digital music
signals– MIDI information tells synthesizer
• When to start and stop playing a note• Volume• Modulation
• Software is available for composing and editing per MIDI standard
Terminals
• Device that provides input and output capabilities
• Dumb terminal– Keyboard and monitor– Connects to host for processing
• Intelligent terminal– Keyboard, monitor, memory, and processor– Connects with host
• Point-of-sale terminal (POS)– Input and output device– Captures retail data
Computer Graphics
• Business
• Education
• Science
• Sports
• Computer art
• Entertainment
Business Graphics
• Types– Maps– Charts
• Help– Compare data– Spot trends– Make decisions quickly
• Attention-getting
• Updated instantaneously
• Rendered quickly
Video Graphics
• Animated graphics
• Prepared one frame at a time
• Examples– Cartoons– Commercials without
humans– Television network’s logo– Arcade games
CAD/CAMComputer-Aided Design
Computer-Aided Manufacturing
• CAD– Software creates 2-D and 3-D designs
• CAM– Controls production equipment
• CIM (Computer Integrated Manufacturing)– Bridge between design and manufacturing – CAD/CAM integrated into manufacturing process– Provides balanced, efficient production process
Ethics and Data
• Computer data can be– Used– Sold– Altered
• What is legal? THIS WE WILL SEE IN CHAPTER 12