Chapter 4

Teachers Discovering ComputersIntegrating Technology and

Digital Media in the Classroom7th Edition

Hardware for Educators

Chapter 4

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Chapter 4: Hardware for Educators 2

Chapter Objectives

Describe the system unit Define the term bit and describe how a series of

bits are used to represent data Identify the major components of the system unit

and explain their functions Explain how the CPU uses the four steps of a

machine cycle to process data Describe the four types of input as well as input

devices and pointing devices List the characteristics of a keyboard and identify

various types of keyboards



Chapter Objectives

Differentiate among the four types of output Identify different types of output devices Explain differences among various types of

printers Differentiate between storage and memory Identify types of storage media and devices Differentiate between CDs, DVDs, and BDs



The System Unit

System unit Boxlike case that houses

the electronic components a computer uses to process data



The Components of the System Unit

The Motherboard Contains many of the electronic components Chip

A small piece of semiconducting material usually no bigger than one-half-inch square and is made up of many layers of circuits and microscopic components that carry electronic signals




CPU Interprets and carries out the basic instructions that

operate a computer Microprocessor manages most of a computer’s

operations




The Control Unit A component of the CPU that directs and coordinates most

of the operations in the computer Fetch - get the next instruction from memory Decode - translate the instruction Execute - carry out the command Store the result - write the result to memory Machine cycle




The Arithmetic/Logic Unit Performs the execution part of the machine cycle Arithmetic (addition, subtraction, multiplication,

division) Comparison (greater than, equal to, less than) Logical (AND, OR, NOT)




The System Clock Synchronizes all computer operations Each tick is called a clock cycle Faster clock means more instructions the CPU can

execute each second Speed measured in gigahertz (GHz)




Memory Used to store data and instructions

The operating system and other system software Application software Data being processed by application programs

Bytes are stored at specific locations or addresses




Memory Size of memory is measured by the number of

bytes available Volatile memory – contents are lost when the

computer is turned off Nonvolatile memory – contents are not lost when

the computer is turned off




Random Access Memory (RAM) The memory chips in the system unit When the computer starts, certain operating

system files are loaded from a storage device into RAM

Synchronous Dynamic RAM (SDRAM) Dual Inline Memory Module (DIMM)




Random Access Memory (RAM) RAM Chips

Smaller in size than processor chips

Commonly hold up to 4 gigabytes of memory




Random Access Memory (RAM) Configuring RAM

The more RAM, the more programs and files a computer can work on at once

Software usually tells you how much RAM is required

For an application to perform optimally, you usually need more than the minimum specifications




Read-Only Memory (ROM) Cannot be modified Contents not lost when

the computer is turned off

Flash Memory Type of nonvolatile

memory that can be erased electronically and rewritten on




Expansion Slots and Expansion Cards Expansion slot

A socket on the motherboard that can hold an expansion card

Add new devices or capabilities to the computer Expansion card

Circuit board that enhances functions of a system component and/or provides connections to peripherals

Plug and Play




Removable Memory Devices Flash memory cards USB flash drives PC Cards ExpressCard modules




Ports and Connectors Port

Point of attachment to the system unit Usually on the back and front of the system unit

Connectors Used to plug into ports

Male connectors Female connectors




Ports and Connectors USB USB 2.0 USB 3.0 FireWire Bluetooth



What is Input?

Any data or instructions you enter into the memory of a computer Data – unprocessed items Programs - series of instructions that tells the

computer how to perform a task Commands - an instruction given to a computer

program User responses - responses to questions or

messages from the software



What are Input Devices?

Any hardware component that allows you to enter data, programs, commands, and user responses into a computer




The Keyboard Typing area Numeric keypad Toggle keys Status lights Arrow keys - arrow control keys Function keys Specialized buttons




Pointing Devices An input device that allows you to control a pointer

on the screen Block arrow I-beam Pointing hand




Pointing Devices Mouse

One or two button mouse Scroll wheel Moving the mouse pointer Clicking Dragging Double-clicking Optical mouse Wireless mouse




Touchpad and Pointing Stick Touchpad – small, flat,

rectangular pointing device that is sensitive to pressure and motion

Pointing Stick – pressure-sensitive pointing device shaped like a pencil eraser




Pointing Devices Trackball

Like a mouse, but the ball mechanism is on top

Requires frequent cleaning

Good when you have limited desk space




Pointing Devices Joystick

Uses the movement of a vertical lever Often used with games

Wheel Steering-wheel type input device Used to simulate driving a car or other vehicle




Pointing Devices Touch and multi-touch

screens Monitor has a touch

sensitive panel Used to issue simple

commands or choose from a list of options

Some models of desktop and notebook computers, all tablet computers, and many mobile devices have touch screens

Kiosks




Optical Scanners Captures an entire page of text or images such as

photographs or artwork electronically Converts the text or image on the original

document into digital data that can be stored on a storage medium and processed by the computer




Pen Input Users write, draw,

and tap on a flat surface to enter input

Stylus – small metal or plastic device that looks like a tiny ink pen but uses pressure instead of ink

Digital pen – slightly larger than a stylus and provides more functionality




Digital Cameras Allows you to take

pictures and store the photographed images digitally

Download, or transfer, pictures to your computer




Audio and Video Input Audio input

Entering speech, music, or sound effects Sound card Speech Recognition

Computer’s capability of distinguishing spoken words




Audio and Video Input Video input

Capturing a full-motion recording onto a computer and storing the video on a computer’s storage medium



What is Output?

Text Graphics Audio Video



What are Output Devices?

Any computer component capable of conveying information to the user

Commonly used output devices Display devices Printers Data projectors Facsimile machines Multifunction devices Interactive whiteboards Speakers, headphones, and earphones




Display Devices Screen housed in a plastic or metal case Variety of sizes Cathode ray tube (CRT) Pixels Flat-panel displays

LCD (liquid crystal display) monitors LCD screens Plasma monitors




Plasma Monitors Some can measure more than

150 inches wide Uses gas plasma technology,

which sandwiches a layer of gas between two glass plates




Monitor Quality Resolution (sharpness and clarity)

Expressed as number of columns and rows 1600 x 1200




Televisions iPad users can stream

their music, photos, and videos wirelessly to a display device using AppleTV and AirPlay

With game consoles, such as Microsoft’s Xbox 360, Nintendo’s Wii, and Sony’s PlayStation 3, the output device often is a television




Printers An output device that produces text and graphics

on a physical medium such as paper or transparency film

Hard copy (printout) Portrait orientation vs. landscape orientation Printing requirements vary




Nonimpact Printers Do not strike paper Much quieter Ink-jet printers

Spray tiny drops of ink onto the paper

Both black-and-white and color

Photo printers Produce photo lab

quality pictures Many use ink-jet

technology




Nonimpact Printers Laser printers

High-speed, high-quality nonimpact printer

Very high quality resolution




Data Projectors Allows an audience to

view output LCD projectors Digital light processing

(DLP) projector




Facsimile (Fax) Machine Used to transmit and

receive an image of a document over a telephone line

Stand-alone Fax modem




Multifunction Devices Can print, scan, copy and

fax Less space Lower cost than separate

units




Interactive whiteboards Touch-sensitive device,

resembling a dry-erase board

A presenter controls the computer program used to display the image by:

Clicking a remote control Touching the whiteboard Drawing on or erasing the

whiteboard Writing on a special tablet




Speakers, Headphones, and Earphones Voice output Audio output device Internal speaker



What is Storage?

The media on which data, instructions, and information are kept

The devices that record and retrieve data, instructions, and information

Similar to a filing cabinet



Storage Media and Devices

Storage medium Also called secondary storage Physical material

Storage device Mechanism used to record and retrieve these items

to and from a storage medium Capacity measured in megabytes or gigabytes




Magnetic Disk Uses magnetic patterns to

store data, instructions, and information on the disk’s surface

Formatting is the process of preparing a disk for reading and writing by organizing the disk into storage locations called tracks and sectors




Hard Disks Provide large storage capacity Sizes range from 320 GB to 1.5 TB Consists of several inflexible, circular disks, called

platters Magnetic storage device Formatting




Miniature and Portable Hard Disks Miniature hard disks are found in consumer

electronics and have greater storage capacities than flash memory

External hard disks connect to a USB or FireWire port by a cable




Solid State Drives A storage device that typically uses flash memory

to store data, instructions, and information and contains no moving parts

Range in size from 16 GB to 512 GB Used in all types of computers




Optical discs Type of storage medium that consists of a flat,

round, portable disc made of metal, plastic, and lacquer that is written to and read from using a laser




CDs and DVDs Optical storage media Used to distribute software Laser reads pits on the surface Used on multimedia computers Several types




Care of Optical Discs Can last up to 100 years if properly cared for Never bend a disc Avoid extreme temperatures and humidity Keep away from contaminants Do not stack or touch discs Use a protective case (jewel box or disc storage

case)




CD-ROM Compact disc read-only

memory Can contain text,

graphics, video, as well as sound

Can hold up to 1 GB Used to distribute

software




CD-R and CD-RW Compact disc-recordable

Can write on each part of the disc only one time Cannot be erased

Compact disc-rewriteable Can write on multiple times Erasable disc




DVD and BD Digital video disc read-only memory (DVD-ROM)

Can store from 4.7 GB to 17 GB High quality DVD-ROM drives

BD (Blu-ray Disc) has storage capacities of 100GB, with expectations of exceeding 200 GB




Miniature Mobile Storage Media




USB Flash Drive Storage device that plugs into a USB port on a

computer or mobile device Smart Card

Similar in size to a credit card Stores data on a thin microprocessor embedded in

the card Cloud Storage

Rapidly growing Internet service that provides storage to computer users

Apple’s iCloud


Chapter 4

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