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