Chapter 2: Looking at Computers: Understanding
Understanding Your Computer
Computers Are Data Processing Devices
Computer: data processing device that performs 4 major functions:
o Input: gathers data, or allows users to enter data
o Process: manipulates, calculates, or organizes data into info
o Output: displays data and info in form suitable for user
o Storage: saves data and info for later use
What is the difference b/w data and information?
Data :representation of a fact, a figure, or an idea (ie. a number, a word, picture, recording etc= little
meaning to u) (ie. number 3578389 and name Zoe Deschanel)
Information: data organized/presented meaningfully (ie. comp. gives computer listing showing Zoe can
be reached by phone at (713) 555-3297= data is useful)
How do computers interact with data and information?
Computers good for processing (manipulating, calculating, or organizing) data into information
(input data, process data into info, output info)
Ie) come to Guelph= give personal data and dig photo (data) to comp, process= ID card (organized
output of data); info stored into comp. for later
Bits and Bytes: The Language of Computers
How do computers process data into information?
Computer uses numbers to process data information
uses language they understand: binary language: consist of 2 digits (0 and 1) to do things like
processing data, print report, edit photo,
binary digit (bit): each 0 or 1
byte: 8 binary digits (bits) combined
o a byte in evry letter, number, special character (@): K: 01001011
What else can bits and bytes be used for?
Also are what computer uses to represent quantity of data and info that it inputs and outputs
o Word files, digital pics, etc : series (millions) of bits and bytes
To measure big files: use kilobytes (KB-1000 bytes), megabytes (MB- 1 mill bytes), gigabytes (GB-
1bill bytes), terabyte (TB): 1 trillion bytes(comp store)
How does your computer process bits and bytes?
Combination of hardware and software used= process data and complete tasks (write letter, play
Hardware: any part of computer u can physically touch
Software: (w/out= cant do anything): set of comp programs which allows hardware to perform
o Categories: application software , system software
Application software: programs used on computer to carry out tasks (ie) type doc, edit photo,
System software: programs that allow application software and hardware devices to work
together o Ie) operating system (OS): common type; program controls comp. system functions,
manage hardware (monitor, printer), allow user to interact w/ computer
Types of Computers
Are all computers the same?
two basic designs of computers: portable and stationary
notebook computer: (laptop computer) portable computer that has keyboard, monitor, etc in
one compact case
o power: battery unit, AC adapter
netbook: small, light weight notebook (7-10 inches), longer battery than notebook
tablet PC: similar to notebook but monitor swivels and fold flat
o input data with a stylus pen across touch screen; input text with virtual keyboard
tablet computer: (ie. Apple iPad) mobile computer with flat multitouch-sensitive screen, virtual
keyboard or separate (connect Bluetooth)
desktop computer: stationary with separate case for main comp. component and peripheral
peripheral device: component connected to computer ( moniter, keyboard)
all-in-one computer: (Apple iMac): eliminate need for separate tower cus comp keep comp
processor&memory in monitor unit (many hv touch screen)
Are there other types of computers?
Mainframe: large expensive comp support hundreds of users simultaneously
o Use in insurance companies: ppl working on similar operation
o College use-handle multitude of processing needs throughout campus
o Execute diff comp programs at same time
Supercomputer: perform complex calculations quick and used where complex models requiring
intensive calculations needed
o Ie) weather forecasting, atomic energy research
Designed to execute few programs as quick as possible while mainframes designed to handle
many programs running sm time but slower pace
embedded computer: specially designed, self contained computer chip in another device (ie. ur
car) that hv own programming and not get input from u or interact with other systems
diff parts of comp hardware has one of functions: input, processing, output, or storage
input device: allow u to enter data (text, image, sounds) and instructions (user responses and
commands) into computer (ie. microphone input sound, camera imput image); most common:
o keyboard: used to enter typed data and commands
o mouse: enter user responses and commands
stylus: input device look like pen but like mouse to tap commands or draw
Aren’t all keyboards the same?
QWERTY keyboard (most comp): get name from letters on keyboard, standard English layout,
layout designed to prevent typewriter keys from jamming
o even tho inefficient in speed, publicly prefer over more efficient (ie.Dvorak keyboard)
o Dvorak: puts most used letters on “”home keys” (middle row of keyboard)= reduce
distance fingers travel increase typing speed
What’s special about notebook keyboards?
Save space and weight, have fewer keys (keys have several functions switched through Fn, shift… What are some alternative keyboards?
Flexible keyboards: full sized, can roll up, plug into usb port to use
Virtual laser keyboard: size of cell phone; projects image of keyboard and sensors detect motion of
ur fingers as type on any flat surface
Bluetooth: wireless data transmission standard connecting electronic computing devices
(cellphones, smartphones, comp.) to peripheral devices (keyboard, headset)
DX1 from Ergodex: keyboards for gamers; can put keys on any place of keyboard and program
keys to execute keystrokes/ macros (series of taks) to perform a specific task
How can I use my keyboard most efficiently?
Many keyboards have additional keys for special functions
o Numeric keyboard: enter numbers quick
o Function keys : shortcut for special tasks, referred as “F” keys cus start with F with number
Each software app, own functions to each F key (ie. F2: move text or graphics in
2.9 PG 57 Word but allow editing of active cell in Excel
Many keys universal : F1= help key in most applications
o Control (Ctrl) key: use w/ other keys for shortcut/tasks (ie. Ctrl+B= bold)
o Insert key: a toggle key cus function change b/w 2 options each time pressed; toggle on=
inserts new txt within a line of existing text, toggle off= replace existing w/ new as u type
Other toggle keys that hv off and on function: Caps Lock, Num Lock key
o Windows key: (for Windows operating system)use alone= open Start menu ; or with others
Window 7/ Vista: Windows + M = minimize all windows; Windows + L= lock comp
Are all conventional keyboards connected to the computer via wires?
Wireless keyboards: powered by batteries, send data to comp with radio frequency (RF)
o Radio transmitter in keyboard send radio wave signals receive through receiving device
pligged into USB port/ Bluetooth device
o 6-30 ft from comp according to quality; 100 ft away for business or auditoriums
Mice and Other Pointing Devices
What kinds of mice are there?
Optical mouse: use internal sensor/laser to detect movement and send to comp to tell where to
move on screen (not require mouse pad but use to enhance movement on uneven surface)
U have ergonomic needs= customize mouse : 3 buttons to open shortcut menus, fit hand grip,
adjustable weight= good fit and control
Similar to wireless keyboard: battery to send data to comp by radio frequency/ Bluetooth
With RF keyboard and mouse= share sm receiver but for notebook, mice hv own receiver clip on
bottom of mouse
Apple: Magic Mouse: multi-touch wireless mouse; top surface is button for scroll, swipe across
mouse= move through pgs, tap mouse to click/doubleclick
MoGo mouse: fits into side of notebook, protects, and charges it; wireless; bluteooth to send data
What other tasks can be done with a mouse?
Magnifier: box drag around screen to magnify hard to read (used by ppl w/ visual disabilities)
Web search: allow to quickly highlight word/phrase and press search on mouse= Web search
File storage: includes wireless USB receiver containing flash memory to store/backup files
Do notebook computers include a mouse?
Most have touch pad (trackpad): small, touch sensitive area at base of keyboard use by move
fingers across it (Mac: multi-touch trackpad: 1,2,3, or 4 finger action)
o Most sensitive to taps, interprete as clicks; many notebook have button underneath pad for
o Many notebooks hv : trackpoint device (joystick like nub to move cursor w/ tip of finger) What input devices are used in games?
Game controllers: force feedback joysticks steering wheels : connect to comp.
o Deliver data in both directions: translate ur moves to comp & translate its response into
forces on ur hands= better experience (some wireless-Wii-= more mobility)
Gaming consoles: PlayStation and XboX 360 use w/ comp w/ buttons and pointing devices
How else can I input data and commands?
Touchscreen: display screen that responds to commands by touch with finger/ stylus
o Becoming pop now with cell phone and tablet computers
Tablet PC has built in keyboard but touch screen better with virtual keyboard onscreen when need
(have basic keysand special keys to switch b/w numbers, punctuation etc)
All in one desktop Pcs, and other desktop and notebook comp hv touch screen and portable media
players (Apple iPod Touch: touch capability; nitendO DS
Digital notes= use digital pen with flash drive: portable electronic storage device that connect to
a USB port on computer; can write on any conventional paper which is captured into flash drive
and store; flashdrive connect to comp. = digital text
How can I input digital images into my computer?
Dig. Camera, cell phone, camcorder take pic and video and are input devices used in remote
settings (away from comp) and downloaded later to comp w/ data cable or wirelessly, recognized
Scanner: also input images by creating digital image (printed, saved in storage, or emailed)
How do I capture live video from my computer or device?
Webcam: small camera on top of monitor connect by cable or built into tablet/notebook comp
o Takes pics but used most to capture/ transmit live video (HD)
o Videoconferencing tech (video call) across internet w/ webcam and microphone (ie. ooVoo:
video call with max 12 ppl)
Can exchange files, swap comp control, txt msg during call
Why would I want to input sound to my comp?
With sound input, can have convos with others, conference with work colleagues, record podcast..
Requires microphone (mic): allow u to capture sound waves (ie. ur voice) and transfer them to
digital format on ur comp.
Many notebooks and desktop comp come w/ built in mic
What types of microphones are available?
Unidirectional microphones: pick up sound from 1 direction (record podcast, phone calls)
Omnidirectional: pick up sounds from all directions at once (record +1 voice-conference call)
Bidirectional:receive sound equally from front and back of mic (interviews)
Clip-on microphones (lavalier microphones): presentations where hands free for other activities
(write on board, move around room)
Close-talk microphones: usually attatched to headset usingspeech-recognition software=
videoconferencing/ phone calls (hands are free and headset allows u to listen too)
What input devices are available for ppl with disabilities?
Visually impaired users: voice recognition (if less severe, make larger keys)
o Keys on touch screen easier
Can only use one hand: Maltron keyboard Motor control issues (difficulty with pointing devices): trackballs manipulate w/ one finger and
attatched to any surface (wheelchair)
Arm motion restrain: head mounted pointing devices used (camera on monitor and device to head
(on a hat) ; move head= camera detect and controls cursor on screen; click= move device in hand,
feet, mouth-blow it= sense it)
Output device: allow u to send processed data out of comp as text, pics, sounds, or video
o Ie. monitor (display screen): display text, pic, video as soft copies (only see onscreen)
o Ie. printer: create hard copies ( copies u can touch) of text and graphics
o Speakers, earphones: output for sound
What are the different types of monitors?
Common: liquid crystal display (LCD) :aka flat-panel monitor is light and energy efficient
Light emitting diode (LED): in newer monitors, more energy efficient, better color accuracy,
thinner panels (replaced cathode ray tube- CRT- monitor)
o CRT is legacy technology (computing devices/peripheral that use techniques parts, and
methods no longer popular); can still be used but when monitor fails, replace with LCD
Organic light-emitting diode (OLED) displays: : use organic compounds that produce light
when exposed to electric current
o Unlike others, no need backlight to function= less power needed (run longer on single
battery than LED), thinner display (3mm), brighter, more environ. Friendly than LCD
o Use: cell hpone, media player, camera
How do LCD monitors work?
Grid of tiny dots (pixel) create image on monitor; made of 3 subpixels of red, blue, green (newer
tv= 4 color yellow)
Made of 2+ sheets filled with liquid crystal solution; fluorescent panel at back of monitor makes
Electric current pass liquid crystal sltn=crystal move and block fluorescent/ let shine through=
image form on screen (color from subpixel combos)
What factors affect quality of LCD monitor?
Aspect ratio: width-to-height proportion of monitor (b4= 4:3 ; now 16:9 or 16:10)
The screen resolution (clearness/sharpness of image) reflects # of pixels on screen
o 1600( # of vertical columns) X 1200 (# of pixels in each column)
o resolution of LCD monitor depend on screen size and aspect ratio
(can change resolution on it but still distorted)
Contrast ratio: measure of diff in light intensity b/w brightest white and darkest black produced
o ratio low= colors fade when adjust brightness (prefer 400:1 and 1000:1)
o when backlight turn off completely and not dimmed to lowest setting= 10000:1 or 50000:1
not used normally unless LED
Viewing angle: (measure in degrees) tell how far u can move to side/above/below monitor b4
image quality go to unacceptable levels (17 inchees + monitor= atleast 150 degree angle recomend
Brightness: (measured in nits – cd/m^2): measure of greatest amount of light showing when
monitor show pure white (300 cd/m^2 recommended)
Response time: (milliseconds) measure time takes for pixel to change color (lower response=
faster transitions=moving image appear smooth on screen)
Is bigger screen size always better?
>monitor= display more (size may matter depend on what displayed larger panel= more pixels (blueray movies need more pixels to display it)
o view multiple doc or web pgs at sm time
BUT: cost: cheaper to buy 2 small than 1 big monitor
What other features should I look for in an LCD monitor?
Built in features: speakers, webcams, microphones, multiformat card reader (display images
directly on monitor/ download pictures quickly from camera memory card to PC)
Built in USB port: easy to connect extra peripherals; video ports (connect DVD player/ games)
How do I show output to a large group of people?
Projector: a device that can project images from ur computer onto a wall or viewing screen
o use in in business, education settings (presentations)
o ie) 3M MPro 150: small, light, portable
o Entertainment projectors (ie. Wonderwall): have stereo speakers and multimedia
connectors= good for home for shows, dvds, images, video games in bigger format
o HDMI port on laptop= connect to HDTV w/ one cable (DVI port works too)
Different types of printers
2 categories: inkjet and laser (both nonimpact)
nonimpact printer: spray ink/ laser beams transfer marks onto paper
impact printer: small keys strike paper through inked ribbon= marks on paper (not common)
o ie) dot- matrix printer
Advantages of inkjet printers
inkjet printer: spray tiny drops of ink onto paper (great for black and white txt and color images)
affordable, high quality prints quick and quietly, professional look when print w/ right paper
when buy: look at type and cost of ink cartridge needed (some use 2: black and color; others 4)
Why would I want laser printer?
Faster printing speed than inkjet printers, higher