introduction computer hardware jess role @ueab 2006 input/output printer,scanner and monitor

Introduction Computer Hardware Jess Role @UEAB 2006

INPUT/OUTPUT PRINTER,SCANNER AND

MONITOR


What Is Input?What is input?

• Any data or instructions you enter into the memory of the computer

• Users can input data and instructions in a variety of ways


What Is Input?What are two types of input?

• Data– A collection of

raw unprocessed facts, figures, and symbols

• Instructions– Programs– Commands– User responses

DATA Bradley Kinkade 42 hours $12.50 per hour

hard disk

COMMANDS

print th

e timecard

PROGRAMS

timecard

USER RESPONSES

Yes, the tim

ecard entries are corre

ct

No, the tim

ecard entries are not corre

ct

INSTRUCTIONS


What is Input?What are the three forms of instructions?

Program

A series of instructions that tells a computer how to perform the tasks necessary to process data into information

User response

An instruction you can issue by replying to a question that a computer program displays

Command

An instruction given to a computer program

Users can issue commands by typing or pressing keys on the keyboard, clicking a mouse button, speaking into a microphone, or touching an area of a screen


What is Input?What are two features of most programs today?

• Menu-driven program– Provides menus as a means of entering commands– Menus contain a list of options from which you select

Graphical user interface (GUI)

• Uses icons, buttons, and other graphical objects that allow you to select and issue commands

icons

icons

menu

buttons


What are Input Devices?What is an input device?• Any hardware component that allows you to enter

data, programs, commands, and user responses into a computer

scanners and reading devices

voice input

keyboard

pointing device

video input

digital camera


The KeyboardWhat is a keyboard?• An input device that contains keys you press to enter data

into the computer• Typing area

– Letters of the alphabet, numbers, punctuation marks, and other basic keys

Numeric keypad

• Calculator-style arrangement of keys

numeric keypad

typing area

function keys

Function keys

• Special keys programmed to issue commands toa computer


Toggle key• Switches between

two different states such as the NUM LOCK or CAPS LOCK keys

Keys to position the insertion point• Insertion point is a

symbol that indicates where on the screen the next character you type will display

The KeyboardWhat are some special types of keys?

• SHIFT, CTRL, ALT and others– Used in combination with other keys to issue commands

insertion point

insertion point

pointerpointer


The KeyboardWhat is an ergonomic keyboard?• Designed to minimize strain on your hands and

wrists Ergonomics

incorporates comfort, efficiency, and safety into the design of items in the workplace


Pointing DevicesWhat is a pointing device?• An input device that

allows you to control a pointer on the screen

• A pointer is a small symbol on the screen

• The pointer takes several shapes

I-beam

pointing hand

block arrow


MouseWhat is a mouse?• A pointing device that fits

comfortably under the palm of your hand

• The most widely used pointing device on desktop computers

• The mouse controls the movement of the pointer, also called the mouse pointer, on the screen


A mouse pad provides better traction and protects the ball from a build up of dust and dirt

• A rubber or metal ball is on its underside

• When the ball rolls in a certain direction, electronic circuits in the mouse translate the movement of the mouse into signals the computer understands

MouseHow does a mechanical mouse work?

mouse padmouse pad

ballball

wheel buttonwheel button

mouse buttonsmouse buttons


MouseHow does an optical mouse work?• Uses devices that emit

and sense light to detect the mouse’s movement

• Some use optical sensors; others use laser

• More precise than a mechanical mouse and does not require cleaning

• Slightly more expensive

back buttonback

button

wheel buttonwheel button

forward button

forward button

optical sensor

optical sensor


• Point

• Click

• Right-click

• Double-click

• Drag

• Right-drag

• Rotate wheel

• Press wheel button

Press and release the primary mouse button, which usually is the left mouse button

Click

Move the mouse across a flat surface until the pointer on the desktop rests on the item of choice

Point

Roll the wheel forward or backward

Rotate wheel

Quickly press and release the left mouse button twice without moving the mouse

Double-click Point to an item, hold down the right mouse button, move the item to the desired location on the screen , and then release the right mouse button

Right-drag

Press the wheel button while moving the mouse on the desktop

Press wheel button

Point to an item, hold down the left mouse button, move the item to the desired location on the screen, and then release the left mouse button

Drag

Other Pointing DevicesWhat are some common mouse operations?

Press and release the secondary mouse button, which usually is the right mouse button

Right-click


Other Pointing Devices?What is a trackball?

• A stationary pointing device with a ball on its top

• To move the pointer, you rotate the ball with your thumb, fingers, or the palm of your hand

trackball


Other Pointing DevicesWhat is a touchpad? • Also called a trackpad A small flat,

rectangular pointing device that is sensitive to pressure and motion

Typically built onto keyboards of laptop or notebook computers

touchpad


Other Pointing DevicesWhat is a stylus?

• Used in professional graphical applications

• A graphics tablet, also called a digitizer or digitizing tablet, is a flat rectangular, electronic plastic board used with a stylus

Looks like a ballpoint pen, but uses pressure to write text and draw lines

Originally called a pen or electronic penstylus or pen


Other Pointing DevicesWhat is handwriting recognition software?

• Some notebooks and many handheld computers have touch screens that allow you to input data using a stylus

Software translates handwritten letters and symbols into characters that the computer understands


Voice InputWhat is audio input?• The process of entering any sound into the computer such

as speech, music, and sound effects• Requires a sound card• Input sound via a device such as a microphone, tape

player, CD player, or radio• Windows stores audio files as waveforms

– Called WAV files with a .wav extension


Voice InputHow does voice recognition work?

You’re right!

Step 1: User dictates text into microphone.Step 2: An analog-to-digital converter (ADC) translates sound waves into digital measurements the computer can understand. Measurements include pitch, volume, silences, and phenomes. Phenomes are sound units such as aw and guh.

Step 3: The software compares the spoken measurements to those in its database to find a match or list of possible matches.

Step 4: To narrow a list down, the software presents the user with a list of choices or uses a natural language component to predict the most likely match. The user may correct any wrong selection made by the software.

…Your write…You’re right…Your right

Natural Language Engine

your, you’re

right, writeMatches


Voice InputWhat is MIDI?• An external device such as an electronic piano keyboard

used to input music and other sound effects• Music is stored in the computer


Digital CamerasWhat is a digital camera?• Allows you to take pictures and store the photographed images digitally • Images are viewable immediately on the camera

You can download, or transfer a copy of the pictures from the camera to the computer

Images can be edited, printed, or posted on a Web site or photo community


In digital images the pixel is a tiny square

The greater the number of pixels, the better the quality of the image

Digital CamerasWhat is resolution?

• The sharpness and clearness of an image• The higher the resolution, the better the image quality, but

the more expensive the camera• A pixel (picture element) is a single point in an electronic

image


Video InputWhat is video input?• The process of entering a full-motion recording into a computer and

storing it on a storage medium• Also called video capture A video capture card is

an expansion card that converts the analog video signal into a digital signal that a computer can understand

A digital video (DV) camera is a video camera that records video as digital signals

analog video camera

analog video camera

video-in plug

video-in plug

digital video camera

digital video camera


video digitizer

Used to capture an individual

frame from an analog video and

then save the picture in a file

Video InputWhat are some factors related to video input?

video decoder

A card that decompresses

video data

• Video files can require huge amounts of storage space• Video compression is used to decrease the size of the files• Files can be compressed using software or hardware


Scanners and Reading DevicesWhat is a scanner?• A device that captures data directly from source

documents• A source document is the original form of the

data


A flatbed scanner, a more popular type, works similarly to a copy machine except it creates a file of the document in memory instead of a paper copy

Scanners and Reading DevicesWhat is an optical scanner?• Usually called a scanner• A light-sensing input device that reads printed text and

graphics and then translates the results into a form the computer can use


OCR device

Includes a small optical scanner for reading

characters and sophisticated software for analyzing what is

read

Software

Works with an optical scanner to convert a scanned image into a text file that can be

edited

Scanners and Reading DevicesWhat is optical character recognition (OCR)?

• A technology that involves reading typewritten, computer-printed, or handwritten characters from ordinary documents and translating the images into a form that the computer can understand


Scanners and Reading DevicesWhat is a bar code scanner?• Uses laser beams to read

bar codes


Input Devices for Physically Challenged Users

Why are computers important for those with physical limitations?

• Americans with Disabilities Act (ADA) requires any company with 15 or more employees make reasonable attempts to accommodate the needs of physically challenged workers

• Many input devices address the needs of users with physical limitations



What is a keyguard?• A metal or plastic plate placed over the keyboard Allows users to rest

their hands on the keyboard without accidentally pressing any keys

Also guides a finger or pointing device so a user presses only one key at a time

For users with limited hand mobility



What is an on-screen keyboard?• A graphic of a

standard keyboard that displays on the user’s screen

• A pointing device is used to press the keys



What options are available for users with motor disabilities?

• A handheld switch can be used as a pointing device

• A portable computer or pointing device can be mounted to a wheelchair

• People with limited hand movement can use a head-mounted pointer


Implantation

• For paralyzed or speech impaired individuals

• A doctor will implant a computerized device containing a transmitter into the brain

• As the users thinks, the transmitter will send signals to the computer

Gesture recognition

• Computer will be able to detect human motions

• Computers with this capabilities have the potential to recognize sign language, read lips, track facial movements, or follow eye gazes


What are new developments in computing that will benefit physically challenged users?

• Developments now in the prototype stage attempt to provide users with a natural computer interface


What is Output?What is output?• Data that has

been processed into a useful form, called information

• A computer generates several types of output

Text

Audio

Video

Graphics


What is Output?What is text?

• Consists of characters that create words, sentences, and paragraphs

What is a graphic? Also called a graphical image A digital representation of

non-text information such as a drawing, chart, and photograph


What is Output?What is audio?• Music, speech, or any

other sound

What is video? Consists of full-

motion images that are played back a various speeds

Most video also has accompanying audio


What are Output Devices?What is an output device?• Any hardware component that can convey

information to a user

printer

monitor speakers


Display DevicesWhat is a display device?• Also called a

display• An output device

that visually conveys text, graphics, and video information

• Information on a display device is sometimes called soft copy


• Contains a cathode ray tube (CRT), a large sealed, glass screen

• The screen is coated with tiny dots of phosphor material

• A pixel, or picture element, is a single point in an electronic image

• Three dots (red, blue, and green) combine to make up each pixel

Display DevicesWhat is a CRT monitor?

CRT monitor screen

cathode ray tube


Display DevicesWhat are typical sizes for CRT monitors?• 15, 17, 19, 21, and

22 inches• Monitor measured

diagonally from one corner of the casing to the other

• The viewable size is the diagonal measurement of the actual viewing area provided by the monitor

screen size

viewable size


Display DevicesWhat is a liquid crystal display (LCD) monitor?

• A type of flat-panel display

• Uses liquid crystals between two sheets of material to present information on a screen

• An electric current passes through the crystals which creates the images on the screen


Display DevicesWhere are some features of LCD screens?• Lightweight and

compact• Consumes less than

one-third of the power than does a CRT monitor

• Come in a variety of sizes

• Ideal for notebook and handheld computers


800 x 600typically the

standard

Display DevicesWhat is display resolution?• Describes the sharpness and clearness of an image• Resolution of a display device stated as dots, or pixels

1280 x 1024maximum resolution

of most monitors

800 horizontal

pixels

600 vertical pixels

Total of 480,000 pixels on screen2048 x 1536

maximum for high-end monitors


Display DevicesWhat is dot pitch?• Another factor used to

measure image clarity• Sometimes called pixel

pitch• The distance between

each pixel on a display• The smaller the

distance between the pixels, the sharper the image

Use a monitor with a dot pitch

of .29 millimeters or lower to

minimize eye fatigue


Should be fast enough to maintain a constant, flicker-free

image

A high-quality monitor will provide a refresh rate of at

least 75 hertz

Display DevicesWhat is refresh rate?• Another factor in a

monitor’s quality• Also called vertical

frequency or vertical scan rate

• The speed that a monitor redraws images on the screen

• Measured according to hertz, which is the number of times per second the screen is redrawn

The image on the screen redraws itself 75 times in a second


Display DevicesWhat is a video card?• Converts digital output

from the computer into an analog video signal

• Sends the signal through a cable to the monitor

• Controls how the display device produces the picture

• Also called a graphics card or video adapter


Step 1Step 1Step 2

Step 1Step 2

Step 3

Step 1Step 2

Step 4

Step 3

Step 1Step 2

Step 3

Step 4

Step 5

Step 2

Step 3

Step 4

Step 5

Step 6

Step 1

Display DevicesHow does video travel from the processor to a CRT monitor?

Step 1: The processor sends digital video data to the video card.Step 2: The video card’s digital-to-analog converter (DAC) converts the digital video data to an analog signal.

Step 3: The analog signal is sent through a cable to the CRT monitor.Step 4: The CRT monitor separates the analog signal into red, green, and blue signals.Step 5: Electron guns fire the three color signals to the front of the CRT.Step 6: An image displays on the screen when the electrons hit phosphor dots on the back of the screen.


PrintersWhat is a printer?

• An output device that produces text and graphics on a physical medium such as paper or transparency film

• A hard copy, or printout, exists physically

• Two orientations

portrait orientation

portrait orientation

landscape orientation

landscape orientation


PrintersWhat is an ink-jet printer?• A type of nonimpact printer

that forms characters and graphics by spraying tiny drops of liquid ink onto a piece of paper

• Usually uses individual sheets of paper stored in a removable or stationary tray

• The most popular type of color printer for use in the home


PrintersWhat is the resolution of a printer?

• Also called sharpness and clarity• Measured by the number of dots per inch (dpi) a printer can

output

300 dpi 1,200 dpi600 dpi


PrintersWhat is a laser printer?

• A high-speed, high-quality nonimpact printer

• Usually use individual sheet of paper stored in a removable tray

• Can print text and graphics in very high quality resolution, ranging from 600 to 1,200 dpi

• Typically costs more than ink-jet printers, but are much faster


PrintersHow does a laser printer operate?• Operates in a manner

similar to a copy machine• Creates images using a

laser beam and powdered ink, called toner

• When toner runs out, you can replace the toner cartridge

• Toner cartridge prices range from $50 to $100 for about 5,000 printed pages


• A page description language (PDL) tells the printer how to layout the contents of a printed page

• Laser printers use a PDL to process and store the entire page before they actually print it so they are sometimes called page printers

• Laser printers require a certain amount of memory in the device to store a page before printing

PrintersWhat is a page description language?

PCL (Printer Control Language)

Developed by Hewlett-Packard

A standard printer language that supports the fonts and layout

used in standard office documents

PostScript

Designed for complex documents with intense graphics and colors

Used by professionals in the desktop publishing and graphic

art fields


PrintersWhat is a dye-sublimation printer?

• A type of thermal printer• Also called a thermal dye transfer

printer• Uses heat to transfer colored dye

to specially coated paper• Cost several thousand dollars• Can create images that are of

photographic quality


Step 1: Insert media card into digital camera. Take the photograph with your digital camera.

Step 2: Remove the media card from the digital camera and insert it into the card slot on the photo printer

Step 3: Select desired image to print, number of copies, and size of print by pushing buttons on the photo printer.

Step 4: Remove the photo from the photo printer

PrintersWhat is a photo printer?

• A color printer that can produce photo lab quality pictures as well as printing everyday documents

• Many photo printers can read media directly from a digital camera


PrintersWhat is a large-format printer?

• Operates like an ink-jet printer, but on a much larger scale

• Creates photo-realistic quality color prints

• Used by graphic artists


Speakers and HeadsetsWhat is an audio output device?

• A component of a computer that produces music, speech, or other sounds, such as beeps

• Two commonly used audio output devices are speakers and headsets

speakers


Speakers and HeadsetsWhat is Internet telephony?• Voice output works with voice input• Allows you to have a conversation over the

Web, just as if you were on the telephone


Other Output DevicesWhat is a data projector?• A device that takes the image from a computer

screen and projects it onto a larger screen so an audience of people can see the image clearly


Other Output DevicesWhat is a fax modem?

• A modem that allows you to send (and sometimes receive) electronic documents as faxes

• Transmits computer–prepared documents, such as a word processing letter, or documents that have been digitized with a scanner, or digital camera

external fax modem

external fax modem

internal fax

modem card in system

unit

internal fax

modem card in system

unit


special-purpose terminals

intelligent terminals

TerminalsWhat is a terminal?

dumb terminals

• A device that performs both input and output because it consists of a monitor (output), a keyboard (input), and a video card

• Three basic categories


TerminalsWhat is a dumb terminal?

• Has no processing power so it cannot function as an independent device

Can enter and transmit data to, or receive and display information from, a computer to which it is connected

Connect to a host computer that performs the processing and then sends the output back to the dumb terminal


TerminalsWhat is an intelligent terminal?

• Has memory and a processor that has the capability of performing some functions independent of the host computer

• Sometimes called programmable terminals because they can be programmed by the software developer to perform basic tasks


TerminalsWhat is a point-of-sale (POS) terminal?• Records purchases at the point

where the consumer purchases a product or a service

• Output from POS terminals serve as input to other computers to maintain sales records, update inventory, verify credit, and perform other activities associated with the sales transactions that are critical to running the business

POS terminal


Output Devices for Physically Challenged Users

What other output options are available for visually impaired users?

• Change Window’s settings such as increasing the size or changing the color of the text to make the words easier to read

• Blind users can work with voice output where the computer reads the information that displays on the screen

A Braille printer outputs information in Braille onto paper

introduction computer hardware jess role @ueab 2006 input/output printer,scanner and monitor

Documents

computer users

computer scanners

computer program users

input devices

types of input

caps lock keys keys

hardware component

screen slide