Chapter 6: Input and Output

input

any data or instructions entered into a computer

input devices

hardware used to translate words, numbers, sounds, images, and gestures that people understand into a form that the system unit can process 

keyboard 

input device that looks like a typewriter keyboard but has additional keys 

3 categories of keyboards

virtual

laptop 

traditional 

virtual keyboard

used primarily with cell phones and tablets

no physical keys

laptop keyboards

attached to laptop system unit and designed to fold up with laptop monitor to easily fit in a backpack or briefcase 

traditional keyboards

full-sized keyboards on desktops and larger computers 

101 keys

toggle keys

turn a feature on or off

combination keys 

perform an action when held down with another key 

pointing devices

provide an intuitive interface with system unit by accepting physical movements or gestures such as a finger pointing or moving across a screen and converting these movements into machine-readable input

touch screen

allows users to select actions or commands by touching the screen with a finger or stylus

stylus 

penlike device typically used with tablets and mobile devices 

handwriting recognition software

translates handwritten notes into a form that system unit can process

multitouch screens

can be touched with more than one finger, which allows for interactions such as rotating objects or zooming in or out

mouse 

controls a pointer that is displayed on monitor 

mouse pointer usually appears in shape of arrow 

wheel button

button on mouse that can be rotated to scroll through information that is displayed on the monitor

cordless/wireless mouse

uses radio waves or infrared light waves to communicate with system unit 

battery 

touch pad

controls mouse pointer to make selections

operates by moving or tapping your finger on surface of a pad

game controllers

devices that provide input to computer games

4 most popular and specialized game controllers

joysticks

gaming mice

gamepads

motion-sensing devices 

joysticks

control game actions by users varying pressure, speed, and direction of a control stick 

gaming mice

similar to traditional mice with higher precision, faster responsiveness, and programmable buttons

gamepads

designed to be held by two hands and provide a wide array of inputs, including motion, turning, stopping, and firing

motion-sensing devices 

control games by user movements 

nintendo’s joy-con controller 

scanning devices

convert scanned text and images into a form that system unit can process

5 types of scanning devices

optical scanners

card readers

bar code readers

RFID readers

character and mark recognition devices

optical scanner/scanner

accepts documents consisting of text and/or images and converts them to machine-readable form

4 basic types of optical scanners

flatbed

document

portable

3D

flatbed scanner

like a copy machine

image to be scanned is placed on a glass surface, and scanner records image

document scanner 

similar to flatbed scanner except it can quickly scan multipage documents 

automatically feeds one page of a document at a time through a scanning surface 

portable scanner

typically handheld device that slides across image, making direct contact

3D scanner

use lasers, cameras, or robotic arms to record shape of an object

cannot recognize light, dark, and colored areas- recognize shape of object they are scanning

card readers 

device that interprets encoded information contained on credit, debit, access, and identification cards 

magnetic card reader

reads encoded info from a magnetic strip on back of card

chip cards

include additional security in form of a microchip embedded in credit card 

chip has encrypted data that makes it nearly impossible for criminals to forge a duplicate card 

bar code readers/scanners

photoelectric scanner that reads bar codes for processing

either handheld wand readers or platform scanners

UPC universal product codes 

one-dimensional bar code made up of vertical zebra strip marks that uniquely identify a product 

automate process to check out customers and maintain inventory records 

QR codes

2-dimensional bar code typically made up of a grid of black and white squares

can be read from any angle and contain more info than a UPC

MaxiCod

QR code used by united parcel service and others to automate process of routing and tracking packages

RFID radio-frequency identification tags 

tiny chips that can be embedded in almost everything 

read using an RFID reader 

character and mark recognition devices 

scanners able to recognize special characters and marks 

3 types of character and mark recognition devices

magnetic-ink character recognition MICR

optical-character recognition OCR

optical-mark recognition OMR

magnetic-ink character recognition MICR

used by banks to automatically read those unusual numbers on bottom of checks and deposit slips

reader/sorter reads these numbers and provides input that allows banks to efficiently maintain customer account balances

optical-character recognition OCR

uses special preprinted characters that can be read by a light source and changed into machine-readable code 

wand reader

optical-mark recognition OMR

senses presence or absence of a mark, such as a pencil mark

used to score standard multiple-choice tests

image-capturing devices 

create or capture original images 

cameras and webcams 

digital cameras

capture images digitally and store images on a memory card or in camera’s memory

webcams

specialized digital video cameras that capture images and send them to a computer for broadcast over internet

audio-input devices 

convert sounds into a form that can be processed by the system unit 

microphone 

voice recognition systems

use a mic, sound card, and special software

allow users to operate computers and other devices, and create documents

output

processed data or information, typically taking form of text, graphics, photos, audio, and/or video

output devices

any hardware used to provide or to create output 

monitor/display screens

present visual images of text and graphics

monitor features

clarity

ability to accept touch or gesture input such as finger movements

clarity

resolution 

dot pitch 

contrast ratio 

active display area 

aspect ratio 

resolution

expressed as a grid of pixels (series of dots that form images)

higher resolution → clearer image

refresh rate

measure of how quickly new images are displayed on monitor

dot pitch 

distance between each pixel 

lower dot pitch → clearer images 

contrast ratios

indicate monitor’s ability to display images

higher ratio → better monitor

active display area

measured by diagonal length of monitor’s viewing area

aspect ratio 

indicates proportional relationship between a display’s width and height 

16:9

flat-panel monitors 

most widely used type of monitor today 

backlit

3 types of flat-panel monitors

LCD

LED

OLED

LCD liquid crystal display

widely used for older monitors and is typically less expensive

LED light-emitting diode 

use similar technology with a more advanced backlighting technology 

better-quality images, slimmer, more environmentally friendly

OLED organic light-emitting diode

replace LED backlighting with thin layer of organic compound that produces light

can be thinner with better power efficiency and contrast ratios

e-books

traditional printed books in electronic format

e-book readers- dedicated mobile devices for storing and displaying e-books, newspapers and magazines

e-ink 

produces images that reflect light like ordinary paper, making display easy to read 

digital/interactive whiteboards

specialized devices with a large display connected to a computer or projector

flexible screens

allow digital devices to display images on nonflat surfaces

foldable screens - Samsung Galaxy Fold

digital projectors 

project images from a traditional monitor onto a screen or wall 

printer

translate information that has been processed by system unit and present information on paper

features of printer

resolution, color capability, speed, memory, duplex printing, connectivity

resolution for printer 

measure of clarity of images

measured in dpi dots per inch 

color capability

option for color or black and white

most common black ink selection is grayscale

speed

number of pages printed per minute

15-19 pages per minute for black and 5-12 pages per minute for color

memory 

store printing instructions and documents waiting to be printed 

duplex printing

allows automatic printing on both sides of a sheet of paper

connectivity

ability of printer to connect to a network

inkjet printers 

spray ink at high speed onto surface of paper 

laser printer

use a laser light beam to produce images with excellent letter and graphics quality

personal laser printers

shared laser printers

3D printers/additive manufacturing 

create 3D shapes by adding very thin layer after layer of material until final shape is fully formed 

thermal printers

use heat elements to produce images on heat-sensitive paper

atms and gas pumps

plotters

special-purpose printers for producing a wide range of specialized output

maps, images, architectural and engineering drawings

speakers

audio-output devices connected to a sound card in system unit

sound card is used to capture as well as play back recorded sound

headphones

typically worn around head providing audio output

headsets 

audio-output devices connected to a sound card in system unit 

sound card is used to capture as ell as play back recorded sound 

multifunctional devices MFD

devices that typically combines capabilities of a scanner, printer, fax, and copying machine 

virtual reality VR

artificial reality created in 3D by computers 

VR head-mounted displays

have earphones for immersive sound, stereoscopic screens to present 3D images, and gyroscopic sensors to interpret head orientation

VR controllers

have sensors that collect data about your hand movements

drones/unmanned aerial vehicles UAVs

take input from a controller 

send back video and sound 

robots

use cameras, microphones, and other sensors as inputs

ergonomics 

study of human factors related to things people use 

treat eyestrain and headache

15 min break every hour or two

position everything about 20 inches away

blue-light blocking glasses and screen covers

treat back and neck pain 

adjust chair and monitor height and angle 

treat repetitive strain injury

ergonomic keyboards

frequent breaks

massage hands