COMPUTERS: TOOLS FOR AN INFORMATION AGE Chapter 5 Input 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 operators commands Sales representative enters an order on a pad Characters displayed as typed text and stored in pad Factory 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 statements Water samples collected and input into computer Used to produce reports that show patterns of water quality

Input Keyboard Pointing devices Source 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 McDonalds 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 screen Communicate commands to operating system by clicking a button Common 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 screen Several 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 pointers 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 click Pointing 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 input Digital cameras Video input Other Sources

User speaks to computer Speech recognition devices convert spoken words into binary digits Most are speaker-dependent System learns the users 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 chip Photo can be downloaded to computer Use photo-editing software to enhance Photos composed of many pixels of color Photos 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 Internet Can capture video from analog sources with video capture card Video Input