Chapter 5 Input and Output

1. Chapter 5Input and Output Computers:Tools for An Information Age

2. 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

3. Examples Instant Reaction • 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 pad • Factory workers punch a time clock as they go from task to task • Produce weekly paychecks and management reports

4. 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

5. Input • Keyboard • Pointing devices • Source data automation

6. 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

7. Ergonomic Keyboards • Designed to reduce or minimize health issues • Provide more natural, comfortable position of wrists, arms, and hands

8. Anatomy of a Keyboard

9. Pointing Devices • 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. MICR • 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

16. 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

17. 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

18. 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

19. Other Sources • Voice input • Digital cameras • Video input

20. Voice Input • 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

21. Digital Camera • 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

22. Video Input • 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