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COMPUTERS:TOOLS FOR AN INFORMATION AGE
Chapter 5Input and Output
How Users See Input and Output
Users submit data (input) to the computer to get processed information (output) Output can be instant reaction to input Also can be separated by time, distance, or both
Items scanned at supermarket Produce item name and price at counter
Forklift operator speaks to computer Forklift obeys operator’s commands
Sales representative enters an order on a pad Characters displayed as “typed” text and stored in
padFactory workers punch a time clock as they
go from task to task Produce weekly paychecks and management
reports
Examples Instant Reaction
Examples Input and Output Separated
Data on checks input into bank computer Computer processes entries once a month to prepare
statementsWater samples collected and input into
computer Used to produce reports that show patterns of water
quality
Input
KeyboardPointing devicesSource data automation
Keyboard
Similar to typewriter keyboard May be part of a personal computer May be part of a terminal connected to a computer in
another location
Can be unique to an industry Keys on McDonald’s keyboards represent Big Mac or
large fries
Ergonomic Keyboards
Designed to reduce or minimize health issues Provide more natural, comfortable position of
wrists, arms, and hands
Anatomy of a Keyboard
Used to position a pointer on the screenCommunicate commands to operating system
by clicking a buttonCommon devices
Mouse Devices used for games Devices used in laptops Others
Pointing Devices
Mouse
The most common pointing device Movement on flat surface causes movement of
pointer on screenSeveral types
Mechanical - small ball on underside rolls as mouse is moved
Optical - uses a light beam to monitor mouse movement
Cordless - uses either infrared or radio waves, rather than a cord, to connect to computer
Trackball and Joystick
Trackball User rolls the ball directly
Joystick Short lever with handgrip Distance and speed of
movement controls pointer’s position
Pressing trigger causes actions to take place
Touchpad and Pointing Stick
Touchpad Rectangular pressure-sensitive
pad Sliding finger across pad moves
pointer Tapping with finger recognized
as clickPointing stick
Small pressure-sensitive post mounted in center of keyboard
Pushing in any direction moves pointer
Other Pointing Devices
Graphics tablet User moves stylus across board Used to create or trace precise
drawings
Touch screen Allows users to touch items on
screen Position of finger on screen
determines item to be input into system
Pen-based computing Use pen-like stylus to input data Often used in PDAs or pocket PCs
Source Data Automation
Use of special equipment to collect data at the source
Primary areas: Magnetic-ink character recognition (MICR) Optical recognition devices Other sources
Uses a machine to read characters made of magnetized particles
Banking industry is a main user of MICR Characters preprinted on lower left-hand side of
check Amount added by MICR when check is cashed
MICR
Optical Recognition
Uses a light beam to scan data and convert to electrical signals
Common Uses: Scanners at supermarkets Document imaging - converts paper documents to
electronic versions
Scanners
Flatbed scanner Typically scans one page at a time Can be used to scan large documents
Sheetfed scanner Motorized rollers feed sheet across scanner head
Handheld scanner Smallest and least accurate
Optical Character Recognition (OCR) software required to convert picture into characters
Other Optical Recognition Methods
Optical Mark Recognition Machine senses marks on piece of
paper
Optical character recognition (OCR) Wand (handheld) reader reads
characters in special typeface
Bar Codes A series of vertical marks Represents a unique code
Universal Product Code (UPC) used as a standard in supermarkets
Voice inputDigital camerasVideo input
Other Sources
User speaks to computer Speech recognition devices
convert spoken words into binary digits
Most are speaker-dependent System “learns” the user’s
voice
Types of systems Discrete word systems - user
must pause between words Continuous word systems -
user can speak normally
Voice Input
User takes photo that is stored on a chipPhoto can be downloaded to computer
Use photo-editing software to enhancePhotos composed of many pixels of colorPhotos stored on removable memory card
Digital Camera
Digital video consists of series of still frames Displayed rapidly enough to give illusion of motion
Web cam used to transmit video over the InternetCan capture video from analog sources with video
capture card
Video Input