introduction computer hardware jess role @ueab 2006 input/output printer,scanner and monitor
TRANSCRIPT
Introduction Computer Hardware Jess Role @UEAB 2006
INPUT/OUTPUT PRINTER,SCANNER AND
MONITOR
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
• 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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
Scanners and Reading DevicesWhat is a bar code scanner?• Uses laser beams to read
bar codes
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
Input Devices for Physically Challenged Users
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
Introduction Computer Hardware Jess Role @UEAB 2006
Input Devices for Physically Challenged Users
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
Introduction Computer Hardware Jess Role @UEAB 2006
Input Devices for Physically Challenged Users
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Input Devices for Physically Challenged Users
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
What are Output Devices?What is an output device?• Any hardware component that can convey
information to a user
printer
monitor speakers
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
• 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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
Step 1Step 1Step 2
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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.
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
• 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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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
Introduction Computer Hardware Jess Role @UEAB 2006
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