Chp2A - Input Devices

8/13/2019 Chp2A - Input Devices

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2013 by the McGraw-Hill Companies, Inc. All rights reserved.

Chapter 2A

Input Devices


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Learning Objectives

2.1 Compare how to interact with an operatingsystem using a graphical user interface and a

command-line interface

2.2 Summarize how to input information into acomputer with a computers keyboard, mouse,

and touch screen

2.3 Describe other ways to input information into a

computer2.4 Explain why and how computer users need to

address the ergonomics of using a computer


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User Interfaces

Operating system basics

Graphical user interfaces

Command-line interfaces


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Operating System Basics

An operating systemcontrols the systems hardware

and interacts with the user and application software

It performs the following functions:

Displays the on-screen elements with which you interactthe user interface

Loads programs

Coordinates how programs work with the computers

hardware and other software

Manages information storage and retrieval


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Graphical User Interface

Graphical user interface (GUI): Users launchprograms and make choices with graphical objects

Shortcuts- small pictures on the desktop which represent

links to resources

Icons- pictures used to represent an object

Elements on the Windows desktop:

Taskbar

Start button Start menu

Quick Launch bar


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Graphical User Interface

When you right-click an object in Windows, a small menuusually appears called a shortcut menu or a context menu

The window currently in use is the active window

Dialog boxes are windows that appear when the OS or

application needs to give you status information Common GUI features of a window

Title bar

Menu bar

Toolbars

Scroll bars


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Command-line Interface

The user enters typewritten commands rather thaninteracting with graphical objects to execute tasks

Users enter commands at a prompton the screen

For example: in DOS, the prompt usually includes the

identification for the active disk drive (a letter followed bya colon), a backslash (\), and a greater-than symbol (>), as

in C:\>


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Common Input Devices

Input devices enable users to enter information andcommands

Ports- connect input and output devices to the

computer.

Many devices connect via USB ports

Common input devices include:

Keyboard

Mouse Trackballs

Touchpads and pointing sticks

Touch screens


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Keyboard

The primary input device for entering text andnumbers

Alphanumeric keys- Letters, numbers, the space bar, and

the Tab, CapsLock, Backspace, and Enter keys

Modifier keys - Alt (Alternate), and Ctrl (Control)

Numeric keypad- A set of numbers, operation signs, and

cursor movement keys

Function keysKeys labeled F1, F2, etc.

Cursor-movement keysNavigate the cursor around the

screen


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Mouse and Trackball

Mouse - a pointing device that is widely used forentering data on a full-sized PC

The pointerallows users to select the specific

graphical objects they wish to activate or change

A mouse may be:

mechanical - sensors read information from a rolling ball

optical - a sensor and image processor reads and interpret

information from a beam of light Trackballa pointing device in which you move the

pointer by rolling a ball


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Using the Mouse

Pointingis moving the pointer to a location on the screen

To click, press and release the button on the mouse

Double-clicking - pressing the primary mouse button twice

Right-clicking- pressing and releasing the non-primary

button

Dragging- pressing and holding the mouse button and

continuing to hold it as you move the mouse

Scrollingis moving a list of information up or down on the

screen


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Touchpads and Pointing Sticks

Touchpad(or trackpad)a pointing device operatedby moving a finger across a small touch-sensitive

surface

A pointing stick is usuallypositioned near the

middle of a portable

computers keyboard

Generic terms includeintegrated pointing

deviceand 3-D point stick


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Touch Screens

Accept input from a usersfingertips directly on the

computer screen

Computers and terminals

with a single purpose usetouch screens offering a

menu of choices

Smart phones and tablet

PCs have more

sophisticated touch

screens


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Inputting Data in Other Ways

Devices for the hand

Optical input devices

Audio input devices

Inputting music Video input devices

Digital cameras


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Devices for the Hand

Pens are used for tablet PCs, PDAs, and otherhandheld computers

Game controllers- input devices designed for a

particular set of games

Game pads- small, flat devices designed to be held with

both hands


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Optical Input Devices

Use light as a source of input

Bar code readersare scanners that read bar codes

QR Codesare a new format for storing data visually

Image scannersconvert any printed image intoelectronic form

Text documents can be scanned with optical character

recognition (OCR) softwareto translate the image into

text

Biometric scanners analyze physical patterns in

humans


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Audio and Visual Input Devices

Audio Input Devices: Microphones are used to record speech

Speechrecognitionor voicerecognitionsoftwaretranslates spoken words into text

Video Input Devices: PC video camerascapture

full-motion video images

A video capture cardlets

the user connect other

video devices to the PC


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Inputting Music

Import files from CDs, MP3players or tape players

A built-in musical

instrument digital interface

(MIDI) port or MIDI adapter

allows the connection of

electronic instruments to

your computer


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Digital Cameras

Digital cameras- portable, handheld devices thatelectronically capture still images

The images may be copied to a PC, where they may

be edited, copied, printed, etc.

Most digital cameras can store dozens to hundreds

of high-resolution images


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Ergonomics and Input Devices

Ergonomicsis the study ofthe physical relationshipbetween people and theirtools

Repetitive stress injuries(RSIs)occur when repetitive,improper use of a musclegroup leads to strain injuries

Carpal tunnel syndrome- a

wrist or hand injury caused byusing a keyboard for longstretches

Documents

Chp2A - Input Devices