COMP 6005 An Introduction to Computing Session Two: Computer Hardware Input and Output.

COMP 6005 An Introduction to ComputingSession Two: Computer HardwareInput and Output

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Introduction

• Input – any data or instructions entered into the memory of a computer

• Output – data that has been processed into a useful form

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Input

• Instructions can be in the form of:– Program: series of instructions telling a

computer what to do and how to do it

– Command: an instruction that causes a particular program to perform a specific action

– User response: an instruction given by a user by replying to a question displayed by a program

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Input Devices

• Any hardware component that permits users to enter data or instructions into a computer

• Popular devices – light pen, keyboard, mouse, stylus, microphone, digital camera, scanner

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Keyboards

• Issue 5-1, pg 232

• Describe the Dvorak keyboard and compare the differences between the commonly used QWERTY keyboard

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Mouse

• Types:– Mechanical

• Rubber or metal ball on its underside• Electronic circuits translate movements into

signals that computer can process– Optical

• Uses devices that emit and sense light to detect the mouse’s movements

• Can be placed on nearly any surface (except glass)

– Cordless• Battery-powered device that transmits data using

wireless techonology (radio wave or infrared light waves)

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Other Pointing Devices

• Trackball

• Touchpad

• Pointing Stick

• Touch Screen

• Stylus and digital pen

• Cursor

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Assignment

• What is a cursor in reference to input devices? Describe and include an image

• Compare and contrast the display pen and the stylus

• Discuss voice recognition and its applications

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Voice and Audio Input

• Voice input– Process of entering data by speaking into a

microphone

• Audio input– Process of entering any sound into the

computer: speech, music, sound effect– Inputs via microphone, tape players,

CD/DVD players, radios being plugged into a port on the sound card

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Discussion

• Looking Ahead 5-1, pg 241

• Issue 5-3, pg 247

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Video Input

• Process of capturing full-motion images into a computer and storing them on a storage medium

• Types:– Digital video cameras– PC video cameras– Web cams

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Other Input Devices

• Scanners– Optical– Optical readers

• Bar code reader

• (Magnetic-ink Character Recognition) MICR Reader

• Data collection devices

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Terminals

• Point-of-Sale terminals

• Automated Teller Machines

• Smart Displays

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Biometric Input

• Fingerprint scanner

• Face recognition system

• Hand geometry system

• Voice verification system

• Iris recognition system

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Biometric Input

• Issue 5-5, pg 261

• http://www.ibiometrics.net/BioBasics.htm

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Input Devices For Differently-Abled Users• Limited hand mobility persons use

a keyguard to stop them from accidentally pressing keys

• On-screen keyboard

• Trackballs attached to a table, whhelchair or held in user’s hand

• Head-mounted pointers can control the pointer or insertion point

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Gesture Recognition

• Still in prototype stage

• Computer detects human motions

• Potential to recognize sign language, read lips, track facial movements, follow eye gazes

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Implants

• Paralyzed or speech impaired individuals can have a doctor implant a computerized device into the brain

• As the user thinks thoughts, the transmitter will send signals to the computer

• Looking Ahead 5-2, pg 264

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Output

• Users view output on:– Screens

• Via PDAs, monitors, notebooks, tablet PCs, smart phones

• Can view web sites, documents, videos, email, etc

– Print it• Can view photographs, black-and-white

documents, coloured graphics

– Hear it through speakers or headset• Can listen to music, sounds, voice messages

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Output

• Four basic categories of output– Sound– Text– Graphics– Video

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Display Devices

• Output device that shows text, graphics and video information

• Types of display devices– CRT monitor– Flat-panel display

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CRT Monitors

• CRT stands for Cathode-ray tube (large, sealed glass tube)

• Originally curved screens; modern day uses flat screens (more ergonomic)

• Produce a small amount of electromagnetic radiation

• Issue 6-1, pg 297

• http://www.webopedia.com/TERM/C/CRT.html

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Flat Panel Display

• Device with a shallow depth that does not use CRT technology

• Examples: LCD monitors, LCD screens, gas plasma monitors, many HDTVs

• Uses liquid crystal display to produce images

• Uses less power than CRT and less space• Used in Tablet PCs, notebooks, smart

phones, PDAs, e-books• Issue 6-2, pg 299

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Flat-panel Display vs Flat Display• Flat-panel display refers to a

display with a shallow depth and uses LCD, gas plasma or some other technology

• Flat display refers to a CRT monitor that has a flat screen

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Some Other Output Devices

• Printers

• Speakers and headsets

• Fax machines and fax modems

• Multifunction peripherals – act as several different devices in one; printer, fax machine, scanner, copier

• Projectors – Looking Ahead 6-2, pg 317

• Force-feedback joysticks and wheels – provides resistance to the user in response to actions taken

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Printers

• Device that produces text and graphics on a physical medium (paper, transparencies, etc)

• Figure 6-16, pg 303

• Looking Ahead 6-1, pg 303

• Issue 6-3, pg 306

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Types of Printers

• Dot-matrix• Ink-Jet• Impact• Line• Nonimpact• Photo• Laser

• Thermal• Mobile• Label and

postage• Plotters and

large-format• Wireless

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Output Devices For Differently-Abled Users• Hearing-impaired users will have

programs display words and no sound• Visually-impaired users can increase

size, change colour• Blind users can work with voice output

instead of using a monitor – computer reads what is displayed

• An alternative for blind users is a Braille printer – information outputted onto paper in Braille

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Discussion

• Issue 6-4, pg 314

• Issue 6-2, pg 299

• Issue 6-5, pg 319

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Assignment

• Read the Special Feature pg 334-345

• Read Chapter 7 for Class preparation

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Links

• Reference– Discovering Computers 2005 by Shelly,

Cashman and Vermaat

• Of Interest– http://www.indigoimage.com/count/– http://www.hp.com/large/ipg/mobileprint

.html– http://wearables.cs.bris.ac.uk/index.htm