1. 2 Technology in Action Chapter 2 Looking at Computers: Understanding the Parts Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

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Technology in Action

Chapter 2Looking at Computers:

Understanding the Parts

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall

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Chapter Topics

• Functions of a computer• Data versus information• Bits and bytes• Input devices• Output devices• Processing• Storage• Ergonomics


© 2008 Prentice-Hall, Inc. 4

Becoming Computer Fluent

• Data processing• Bits and bytes• Computer hardware• Computer software• Computer platforms• Specialty computers


Computers are Data Processing Devices

• Four major functions:– Input data– Process data into information– Outputs data or information– Stores data and information

DATA IN

INFORMATION OUT

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Data vs. Information

• Data: Representation of a fact, figure, or idea • Information: Organized, meaningful data



Computers are Data Processing Devices

• Data is a representation of a fact, figure, or idea.– Data can be a number, a word, a picture, or

even a recording of sound.• Information is data that has been

organized or presented in a meaningful fashion.

• Computers are excellent at processing data into information.


Bits and Bytes:The Language of Computers

• Computers work exclusively with numbers.• To process data into information,

computers need to work in a language they understand.

• The Binary Language consists of just two digits: 0 and 1.

• Everything a computer does is broken down into a series of 0s and 1s.



• Each 0 and 1 is a binary digit or bit.• Eight binary digits (bits) combine to create

one byte.• In computers, each letter of the alphabet,

each number, and each special character consists of a unique combination of eight bits, in binary language.


Bits and Bytes: The Language of Computers

• Bit– Binary digit– 0 or 1

• Byte– Eight bits

• ASCII – Each byte represents a

letter, number or special character

OFF

0ON

1Microchip Switch

10 0 001 1

= 40

0 0 0 0 01 1

= A0



• 00110001 - 1 01000001 - A• 00110010 - 2 01000010 - B• 00110011 - 3 01000011 - C • 00110100 - 4 01000100 - D • 00110101 - 5 01000101 - E• 0100 - A –O 0101 - P –Z• 0110 - a – o 0111 - p – z• 0011 – 0 - 9


How Much is a Byte?NAME ABBREVIATION NUMBER OF

BYTESRELATIVE SIZE

Byte B 1 byte Can hold one character of data.

Kilobyte KB 1,024 bytes Can hold 1,024 characters or about half of a typewritten page double-spaced.

Megabyte MB 1,048,576 bytes A floppy disk holds approximately 1.4 MB of data, or approximately 768 pages of typed text.

Gigabyte GB 1,073,741,824 bytes Approximately 786,432 pages of text. Since 500 sheets of paper is approximately 2 inches, this represents a stack of paper 262 feet high.

Terabyte TB 1,099,511,627,776 bytes This represents a stack of typewritten pages almost 51 miles high.

Petabyte PB 1,125,899,906,842,624 bytes

The stack of pages is now 52,000 miles high, or about one-fourth the distance from the Earth to the moon.

Computer Hardware

• Hardware: Any part of the computer you can touch

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall 13

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Computer Software

• Software: Programs that enable hardware to perform different tasks– Application software

• Programs you use on a computer to help you carry out tasks.

– System software• The program that controls the way in which your

computer functions.• It manages the hardware of the computer

system.



Computer Platforms: PCs and Macs

PC• CPU – Intel, AMD• Operating system – Microsoft Windows

Mac• CPU – Motorola• Operating system – Apple Mac OS

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Types of Computers

• Notebook Computer (Laptop)– A portable computer that is powered by

batteries or an electrical outlet.– Has a keyboard, a monitor, and other

devices integrated into a single compact case.

• Netbook– A small, lightweight notebook computer

that is generally 7 to 11 inches wide and has a longer battery life than a notebook.


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Types of Computers

• Tablet PC– Similar to a notebook but features a

touch-sensitive screen that can swivel and fold flat.

• Desktop Computer– Intended for use at a single location.


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Types of Computers

• Desktop Computer– Consists of a separate case that houses

the main components of the computer plus peripheral devices.• A peripheral device is a component such as

a monitor or keyboard that is connected to the computer.

• An all-in-one computer houses not just the computer’s processor and memory but also its monitor.


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Types of Computers

• Mainframe– A large computer that supports hundreds

of users simultaneously.– Executes many different computer

programs at the same time.• Supercomputer

– A specially designed computer that can perform complex calculations extremely rapidly.


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Types of Computers

• Supercomputer– Used in situations in which complex models

requiring intensive mathematical calculations are needed.• Weather forecasting• Atomic energy research


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Types of Computers

• Supercomputer– The main difference between a supercomputer

and a mainframe is that supercomputers are designed to execute a few programs as quickly as possible whereas mainframes are designed to handle many programs running at the same time but at a slower pace.


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Types of Computers

• Embedded Computer – A specially designed computer chip that

resides in another device.• A car• An electronic thermostat

– Self-contained computer devices that have their own programming and typically do not receive input from you or interact with other systems.



Types of Computers

• PDA• Server• Mainframe• Supercomputer• Microcontrollers

Server

Mainframe Supercomputer

PDA


Computer Hardware

• Input devices• System unit• Output devices• Storage devices


Th

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in in

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pain

Input Devices• Enter data to be processed

– Keyboard– Scanners– Mouse– Trackball– Touch screen– Microphone– Game controller– Digital camera

A BCD


Input Devices

• Devices used to enter data (text, images, and sounds) and instructions into the computer– Keyboard– Mouse / pointing device– Microphone – Scanner– Digital camera Scanner


Input Devices

• The most common input devices are:– Keyboard

• Used to enter typed data and commands

– Mouse/Pointing Device• Used to enter user responses and commands


Keyboard

• The QWERTY keyboard is standard on most PCs

• Enhanced features include number, function and navigation keys.

• Originally designed for typewriters - meant to slow typists to prevent keys from jamming

• Considered inefficient


Dvorak Keyboard

• The leading alternative keyboard• Puts the most commonly used keys at “home keys”

– The keys in the middle of the keyboard

• Reduces the distance your fingers travel for most keystrokes, increasing typing speed.


Specialty Keyboards

• Laptops• PDAs• Wireless• Ergonomic• Gaming

Laptop

Ergonomic

PDA

Specialty Keyboards

• Virtual laser keyboard– About the size of a cell phone– Projects the image of a keyboard

on any surface.– Sensors detect the motion of your

fingers as you “type” on a desk or other flat surface.

– Data is transmitted via Bluetooth technology


Specialty Keyboards

• Configurable Keyboard– The DXI keyboard from

Ergodex allows gamers to move the keys in any position on the keyboard as well as reprogram them.


Keyboards

• All keyboards have the standard set of alphabetic and numeric keys that you regularly use when typing.

• Many keyboards have additional keys that perform special functions;– The Numeric keypad

• Allows you to enter numbers quickly.– Function keys

• Act as shortcut keys you press to perform special tasks.• Each software application has its own set of tasks assigned to

various function keys.


Keyboards

• Many keyboards have additional keys that perform special functions (cont’d):– The Control (Ctrl) key

• Used in combination with other keys to perform shortcuts and special tasks.



Mouse• Rollerball mouse

– The standard mouse has a rollerball on the bottom, which moves when you drag the mouse across a mousepad.

– Less expensive– Harder to keep clean

• Trackball– Has the rollerball on top or on the

side of the mouse, and you move the ball with your fingers, allowing the mouse to remain stationary.

– doesn’t demand much wrist motion, so it’s considered healthier on the wrist.

Wireless

Optical

Trackball

Standard


Mouse• Optical mouse

– Uses an internal sensor or laser to detect the mouse’s movement.

– A bit more expensive than traditional mice, but, because they have no moving parts on the bottom, there is no way for dirt to interfere with the mechanisms and less chance of parts breaking down.

– Needs no mouse pad– Doesn’t need cleaning

Wireless

Optical

Trackball

Standard


Mouse• Game pads

– Have buttons and pointing devices that provide special game input.

• Wireless Mice– Send data to the computer by

radio or light waves.

Wireless

Optical

Trackball

Standard

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New Mouse Features

• Magnifier– Pulls up a magnification box that you can

drag around the screen to enhance viewing of hard-to-read images.


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New Mouse Features

• Customizable buttons– Provides extra buttons on the mouse that

you can program to perform the functions that you use most often to help you speed through tasks.

• Web Search– Allows you to quickly highlight a word or

phrase and then press the search button on the mouse to start a Web search.


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New Mouse Features

• File storage– Includes a wireless USB receiver that

contains flash memory to store or back up your files.



Other Input Devices• Scanners

– Copy imagesfrom existing sources like book pages or printed copies, digitizing them, and making them available for editing or processing in the computer as well as viewing on the screen.

Flatbed

Handheld

Camera Camcorder


Other Input Devices• Digital cameras

– Takes pictures and makes a digital file of the image for editing, printing, or distribution on the Web.

– Digital movies can be created with a digital video camera and edited and distributed electronically.

Handheld

Camera Camcorder

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Other Input Devices• Game controllers

– Joysticks, game pads, and steering wheels are also consideredinput devices because they senddata to the computer.


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Other Input Devices• Touch screens

– A display screen found on desktops, notebooks, tablet PCs, and smartphones that responds to commands enteredwith a finger or a stylus.


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Other Input Devices• Digital pens

– The EPOS Digital Pen works in conjunction with a flash drive. You can write with the pen on any conventional paper,and your writing is captured and then wirelessly transmitted and stored in the flash drive. When the flash drive is connected to a computer, you can use software to translate your writing into digital text.


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Image Input• Digital cameras, camcorders, and cell

phones are common devices for capturing pictures and video.


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Image Input• Webcams are small cameras that usually

sit on top of your computer monitor or are built into your notebook computer.

• Although somewebcams are able to capture still images, webcams generally are used to transfer live video directly to your computer.Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Inputting Sound• A microphone allows

you to capture sound waves (such as your voice) and transfer them to digital format on your computer.

Microsoft Voice Recognition


Inputting Sound• Microphones come with most computers,

but if you didn’t get a microphone with your computer, you may want to buy a desktop microphone if you plan to record your own audio files.

• A headset microphone is best for videoconferencing and speech-recognition uses.



Inputting Sound• Videoconferencing technology allows a

person sitting at a computer equipped with a personal video camera and a microphone to transmit video and audio across the Internet (or other communications medium).



Inputting Sound• In speech-recognition systems, you

operate your computer through a microphone, telling it to perform specific commands or to translate your spoken words into data input.


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Input Devices for the Physically Challenged

• Visually impaired users can input data from voice recognition or by using large keyboards, including touchscreen keyboards.

• Users with severe motor control problems can use special trackballs designed for one-finger use that can be mounted anywhere.


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Input Devices for the Physically Challenged

• When arm motion is severely restrained, head-mounted pointing devices can be used.



Output Devices• Enable us to see or hear the processed

information– Monitor– Speakers– Printers


Output Devices

• Retrieving information (processed data) from the computer.

• Common Output devices: – Monitor

• Displays text, graphics, and video– Soft copy

– Speakers• Sounds

– Printer• Hardcopy


Monitor Types

• CRT Cathode Ray Tube

– Less expensive– Use much more space– Uses more energy– Better viewing angles

• LCD Liquid Crystal Display

– More expensive– Uses far less space– More energy efficient– Less viewable from an angle


CRT Monitors

• A CRT screen is a grid made up of millions of pixels (tiny dots)

• Each pixel is composed of three smaller elements called phosphors.– A substance that emits light when it is charged with electrons

• Each pixel contains a red, a green, and a blue phosphor.• CRT monitors have an electron gun that shoots red,

green, and blue electron beams at the phosphors on the screen.

• The various colors of the image are created by mixing different combinations of red, green, and blue.


CRT Monitors• Uses picture tube technology• Screen size – Diagonal measurement

of the screen (15, 17, 19, 21)• Resolution – Sharpness of the image

determined by the number pixels that the screen can display (800 x 600, 1024 x 768, 1600 x 1200)

• Refresh rate – Number of times per second the electron beam scans the monitor and recharges the illumination of each pixel (60Hz, 75Hz).– 60Hz – The screen is refreshed 60 times each second.

• The faster the refresh rate, the less the screen will flicker, the clearer the image will be, and the less eyestrain you’ll experience.


Liquid Crystal Display

• Liquid crystal solution sandwiched between two transparent layers form images.

• Used for notebook computers, PDAs, cellular phones, and personal computers

Polarizer

Color filter Color filter glass

Glass polarizer

Backlight

Liquid Crystal



• Like a CRT screen, the LCD screen is composed of a grid of pixels.

• Instead of including a Cathode-ray tube, LCD monitors are made of two sheets of material filled with a liquid crystal solution.

• A fluorescent panel at the back of the LCD monitor generates light waves.

• When electric current passes through the liquid crystal solution, the crystals move around,either blocking the fluorescent light or letting the light shine through – causing images to be formed on the screen.



• Two types of LCD monitors:– Passive-Matrix Displays

• An electrical current passes through the liquid crystal solution to charge groups of pixels, either in a row or a column

• This causes the screen to brighten with each pass of electrical current and subsequently fade.



• Two types of LCD monitors:– Active-Matrix Displays

• Each pixel is charged individually, as needed.• The result is a clearer, brighter image with

better viewing angles.


Other Video Output

• Touch-screen monitors double as both input and output devices.

• Data projectors project a computer image to a large screen for sharing with large groups.


Dot-matrix

Printers

Inkjet

Multifunction

Laser

Plotter

Thermal printer

• Impact printers– Dot-matrix

• Nonimpact printers– Inkjet– Laser – Multifunction

• Specialty printers– Plotters– Thermal printers


Printers

• Impact Printers:– Have tiny hammer-like keys that strike the

paper through an inked ribbon• Nonimpact Printers:

– Spray ink or use laser beams to transfer marks onto the paper.


Nonimpact Printers

• Inkjet– Less expensive

device– Full color printing– Slower in pages

per minute (PPM)– More expensive

per page in B&W

• Laser– More expensive

device– Black and White

(Color lasers are very expensive)

– Faster in PPM– Less expensive in

B&W


Printer Factors to Consider

• Speed– Determines how many pages it can print per

minute– Printer speeds vary by model and range from 8 to

30 ppm for both laser and inkjet printers.• Resolution

– Measured in dots per inch (dpi) or the number of dots of ink in a one-inch line.

– The higher the dpi, the greater the level of detail and quality of the image.• For general-purpose printing, 1,200 dpi is sufficient• To print photos, 4,800 dpi is better• The dpi for professional photo-quality printers is twice

that.



• Color Output– The best setup is to have individual ink cartridges

for each color so you can replace only the specific color cartridge that is empty.

• Memory– Printers need memory in order to print.– Inkjet printers run slowly if they don’t have

enough memory.– Laser printers won’t print at all without sufficient

memory.• Rule of thumb:

– 16 MB



• Use and Cost of the Printer– If you will be printing mostly black and white, text-

based documents or will be sharing your printer with others, then a black-and-white laser printer is best because of its printing speed and overall economies for volume printing.

– If you’re planning to print color photos and graphics, then an inkjet printer or color laser printer is the better, more economical choice.

• Cost of Consumables– You should carefully investigate the cost of

consumables (printer cartridges and paper).– The cost of inkjet cartridges can often exceed the

cost of the actual printer when purchased on sale.


Outputting Sound

• Speakers and Headphones


Outputting Sound

• Most computers include inexpensive speakers as an output device for sound.

• These speakers are sufficient to play the standard audio clips you find on the Web and usually enable you to participate in teleconferencing.

• If you plan to digitally edit audio files or are particular about how your music sounds, you may want to upgrade to a more sophisticated speaker system, such as one that includes subwoofers and surround-sound.


Outputting Sound

• Headphones are recommended for laptops when used in proximity to others.

• Studies have shown that excessive volume in headphones can lead to hearing damage.


The System Unit

Box that contains the central electronic components of the computer:– CPU– Memory– Motherboard– Expansion cards– Power supply– Storage devices


The Front Panel

• Drive bays• Memory card

reader• Floppy drive• Productivity

ports• Power button


The Front Panel

• Power Controls– Power-On button

• Used to turn the computer on only. You do not use this button to shut the computer off

– Power-Off• You turn off the power by clicking on a shutdown

icon on the desktop, not by pushing the main power button

• If you do shut off the power using the main power button, some files and applications may not close properly which could cause problems at start-up.


The Front Panel

• Drive Bays– Special shelves reserved for storage devices– Two kinds

• Internal drive bays– Hard Disk Drive

• External drive bays– Floppy Disk– CD/DVD– Zip Drives


The Back

• Peripheral devices (monitors, printers, keyboards, and mice)connect to the systemunit through ports.

• Because peripheral devices exchange data with the computer in various ways, a number of different portshave been created to accommodate them.


The Back• Types of Ports:

–Serial Port• Sends data one bit at a time• Used for slow devices• Data is transferred at a speed of 115 kilobits

per second(Kbps) or 115,000 bits per second

– Parallel Port• Sends data between devices in groups of bits at

speeds of 500 kbps• Used for printers


The Back

• Types of Ports:–Universal Serial Bus (USB)

• Fast replacing traditional serial and parallel ports as the means to connect input and output devices to the computer

• USB 1.1 Ports– Transfers data at approximately 12 megabits per second

(Mbps) • USB 2.0 Ports

– Transfers data at 480 Mbps per second


The Back• Types of Ports:

–Connectivity Ports • Helps you communicate with other

computers• Gives you access to networks and the

Internet• Gives you the ability to function as a fax

machine• Modem Port – Uses a telephone signal to

connect two computers• Ethernet Port – Transfers data at speeds up

to 1000 Mbps for DSL/cable modem


The Back• Types of Ports

–VGA (Video Graphics Array)• Standard port to which monitors connect

–Audio Ports or Jacks• Where you connect headphones and speakers to

the computer


Inside the System Unit• Essential

electronic components used to process data

• Types of components:– Power supply– Hard disk drive– Motherboard– CPU– Expansion cards


Inside the System Unit• Power Supply

– Regulates the wall voltage to the voltages required by computer chips

• Expansion Cards– Circuit boards that have specific functions that augment

the computer’s basic functions– Sound Card

• Provides a connection for the speakers and microphone

– Video Card• Provides a connection for the monitor


Inside the System Unit• Expansion Cards

– Modem Card• Provides the computer with a phone connection

– Network Interface Card (NIC)• Enables your computer to connect with other

computers


The Motherboard

• All boards connect to the Motherboard to receive power.


The Motherboard

• What connects to the Motherboard: – CPU– RAM– Expansion

cards– Chip set– Built-in

components


Storage Devices

• Enable us to store data or information to be accessed again

Hard Disk Drive CD / DVD DriveFloppy Disk

Flash Drive


Hard Disk Drive

• Stores data and program instructions

• Permanent (nonvolatile) storage

• Storage capacities up to 3.5 TB can hold more data than would fit in the books in a school’s library.

• Transfers data in milliseconds


Hard Disk Drive

• Because the hard drive stores all of the computer’s data and programs, special measures are taken to protect the hard drive from any possibledamage.

• The hard drive is enclosed ina case and is not accessiblefrom the outside of the systemunit.


Hard Disk Drive

• An external hard drive is essentially like an internal hard drive.

• It has been made portable by making it small and lightweight and enclosing it in a protective case.

• Some external hard drives have storage capacities of 1 or 2 TB, or larger.


Optical Storage

• Data can be saved to:• A compact disc (CD)• A digital video disc (DVD)• A Blu-ray disc (BD)

• Data is saved as tiny pits that are burned into the disc by a high-speed laser.


Flash Storage

• A flash drive is a way of storing portable data.

• Flash drives plug into USB ports.• Despite their size, flash drives have

significant storage capacity – as much as 250 GB.


Connecting Peripherals

• A port is a place through which a peripheral device attaches to the computer so that data can be exchanged between it and the operating system.• Located on the back and the front of

the system unit.


Connecting Peripherals• Ports

• A Universal Serial Bus port is now the most common port type used to connect input and output devices to the computer.• USB 2.o ports are the current

standard and transfer data at 480 megabits/second (Mbps).

• The new USB 3.0 standard provides transfer speeds of 4.8 Gbps.



• A traditional serial port sends data one bit at a time.• Serial ports were often used to

connect modems to the computer.• A parallel port could send data

between devices in groups of bits at speeds of 500 Kbps• Used to connect printers to

computers.



• The Firewire 400 interface moves data at 400 Mbps.

• The Firewire 800 doubles the rate to 800 Mbps.• Used for devices such as

external hard drives, digital video cameras, portable music players and digital media players.



• The FireWire 3200 standard has yet to reach the market.



• The Ethernet Port gives you access to networks.• Transfers data at speeds up to

1,000Mbps.• The Modem Port is used to connect to

the Internet over a phone line.• The Video Graphics Array (VGA) port

if the port to which CRT monitors connect.



• The latest digital connector designed for use in high-definition home theater environments is High-Definition Multimedia Interface (HDMI)• A compact audio-video interface that

carries both high definition video and uncompressed digital audio on one cable.


Expansion Cards

• Adds functions• Clip into an open expansion slot on the

motherboard.• Provides new connections for peripheral

devices• Common types:

– Sound– Modem– Video (VGA)– Network (NIC)


Setting it all up: Ergonomics

• Ergonomics refers to minimizing injury or discomfort while using the computer

• Steps to follow:– Position monitor correctly– Use adjustable chair– Assume proper position

while typing– Take breaks– Ensure adequate lighting

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Chapter 2 Summary Questions

• What exactly is a computer, and what are its four main functions?


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• What is the difference between data and information?


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• What are bits and bytes, and how are they measured?


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• What devices do I use to get data into the computer?


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• What devices do I use to get information out of the computer?


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• What’s on the motherboard?


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• Where are programs and information stored?


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• How are devices connected to the computer?


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• How do I set up my computer to avoid strain and injury?


Chapter 2 120

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1. 2 Technology in Action Chapter 2 Looking at Computers: Understanding the Parts Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall