CHAPTER 4 Hardware applications for Education CHAPTER 4 Hardware applications for Education.

CHAPTER 4CHAPTER 4

Hardware Hardware applications for applications for EducationEducation

CHAPTER 4CHAPTER 4

Hardware Hardware applications for applications for EducationEducation

The System UnitThe System Unit

Box-like case that houses the electronic components of the computer used to process data

All computers have a system unit

Sometimes called the chassis

What is the system unit?

Processor Memory module

Processor Memory module Expansion cards

• Sound card• Modem card• Video card• Network

interface card

Ports and Connectors


• Sound card


• Sound card• Modem card


• Sound card• Modem card• Video card


• Sound card• Modem card• Video card• Network

interface card

Processor


What are common components inside the system unit?


What is the motherboard? Also called the system board Main circuit board in the

system unit Contains many

electronic components

Central Processing UnitCentral Processing Unit

What is the central processing unit (CPU)? Interprets and carries out the basic instructions that operate a

computer Most devices communicate with the CPU in order to carry out a task Also called the processor

What is a personal computer processor? The single processor chip found in personal

computers Sometimes called a microprocessor Processors identified by

• Manufacturer

• Model name or model number


Pentium® 4

Celeron™ Duron™

Athlon™


What are the components of the central processing unit (CPU )?

CPU

Arithmetic/Logic Unit

(ALU)

Control Unit

CPU


(ALU)


What is the control unit?

Control UnitControl Unit

The control unit repeats a set of four basic operations:

Fetch – obtain a program instruction or data item from memory

Decode - translate the instruction into commands

Execute - carry out the command Store - write the result to memory

A component of the CPU that directs and coordinates most of the operations in the computer

Together the four operations of the CPU comprise a machine cycle

Also called an instruction cycle

• Execution time (e-time) – time it takes to execute and store

e-time

• Instruction time (i-time) - time it takes to fetch and decode

i-time


What is a machine cycle?


A student enters a math problem into the memory of the computer

Step 1: The control unit fetches the math problem from memory

Step 2: The control unit decodes the math problem and sends it to the ALU

Step 3: The ALU executes the math problem

Step 4: The results of the math problem are stored in memory

The result in memory displays on the screen of the monitor

What is a machine cycle?Together the four operations of the CPU comprise a

machine cycle

CPU

Control Unit

What is the arithmetic/logic unit (ALU)?


.and.

.and.

.not.

.not..or..or.

Component of the CPU Performs arithmetic, comparison, and logical

operations Performs the execution part of the machine cycle


(ALU)

Data RepresentationData Representation

How do computers represent data?

1 1 1 1 1

0 0 0 0 0

Most computers are digital

• Computers are electronic devices powered by electricity, which has only two states, on or off

• Computers recognize only two discrete states: on or off

on

off


What is the binary system?

Binary Digit (bit)

Electronic Charge

Electronic State

A number system that has just two unique digits, 0 and 1• A single digit is called a bit (binary digit)

• A bit is the smallest unit of data the computer can represent

• By itself a bit is not very informative

The two digits represent the two off and on states


What is a byte?

8-bit byte for the number 3

8-bit byte for the number 5

8-bit byte for the capital letter T

Eight bits are grouped together to form a byte 0s and 1s in each byte are used to represent

individual characters such as letters of the alphabet, numbers, and punctuation


What are two popular coding systems to represent data?

American Standard Code for Information Interchange (ASCII)

Extended Binary Coded Decimal Interchange Code (EBCDIC)

• Sufficient for English and Western European languages

Unicode often used for other languages


What is the system clock?

Synchronizes all computer

operationsEach tick is a clock cycle

Fasterclock speed

means the CPU can execute more instructions each

second

Clock speed (clock rate) measured in megahertz (MHz) and gigahertz

(GHz)

MHz - one million ticks of

the system clock

GHz – one billion ticks of

the system clock

Step 2:An electronic signal for the letter T is sent to the system unitStep 3:The signal for the letter T is converted to its ASCII binary code (01010100) and is stored in memory for processingStep 4:After processing, the binary code for the letter T is converted to an image on the output device


How is a character sent from the keyboard to the computer?

Step 1:The user presses the letter T key on the keyboard

MemoryMemory

What is memory?

operating system and other system software that control the usage of the computer

equipment

application programs that carry out a specific task

data being processed by application programs

Three basic items stored in memory

Temporary storage place for data, instructions, and information

Consists of one or more chips on the motherboard or some other circuit board

MemoryMemory

How is memory measured? Size of memory is measured by the number of

bytes available

• Kilobyte - 1,024 bytes

• Megabyte - one million bytes

Volatile MemoryVolatile MemoryLoses its contents when Loses its contents when the computer's power is the computer's power is

turned offturned off

volatile memoryLoses its contents when the computer's power is

turned off

MemoryMemory

What are the two types of memory in the system unit?

nonvolatile memory

Does not lose its contents when the

computer’s power is turned off

MemoryMemory

Memory chips that can be read from and written to by the processor and other devices

When the computer starts, operating system files are loaded from a hard disk into RAM

What is random access memory (RAM)?

As additional programs and data are requested, they also load from storage into RAM

Most RAM is volatile

Storage (hard disk)

RAM

Step 3: When you quit Word, RAM may be used to store another program or data. The program is removed from the screen and the operating system’s user interface redisplays.

Step 1: When your computer is running, certain operating system files are in RAM. Shown here is the operating system’s user interface.

Step 2: When you start a word processing program such as Word, the program loads into RAM from a hard disk. As you create a document, it is in RAM and displays on your screen.

Step 4: When you start a spreadsheet program such as Excel, the program loads into RAM from a hard disk. As you create a spreadsheet, it is in RAM and displays on your screen.

MemoryMemory

How are applications transferred in and out of RAM?

Step 5: When you quit Excel, RAM may be used to store another program or data. Excel is removed from your screen and the operating system’s user interface redisplays.

MemoryMemory

What is a memory module?

single inline memory modules (SIMMs)

Rambus® inline memory module (RIMM)

Small circuit board with RAM chips, which are smaller in size than processor chips

Inserts into the motherboard Three types: SIMMS, DIMMS, and RIMMS

dual inline memory modules (DIMMs)

MemoryMemory

What is a memory module?

dual inline memory module (DIMM)

memory chip

RAM chips usually reside on a small circuit board which inserts into motherboard

MemoryMemory

What is read-only memory (ROM)?

BIOS

(basic input/output system)

Stored on ROM

Sequence of instructions the computer follows to

load the operating system and other files when you first turn on the computer

Nonvolatile — Contents not lost

when the computer is turned off

Memory chips that contain data, instructions, or information that is recorded permanently

Data can only be read,

cannot be modified

Expansion Slots and Expansion CardsExpansion Slots and Expansion Cards

What is an expansion slot? An opening, or

socket, where a circuit board can be inserted into the motherboard

Used to add new devices or capabilities to the computer

Other terms for a circuit board include card, expansion card, expansion board, board, adapter card, adapter, interface card, add-in, and add-on

Modem card also called an internal modem


What are four common types of expansion cards?

Network interface

card (NIC) also called a network

card

Sound card

Video card also called

video adapter or graphics

card


The computer automatically can

configure cards and other devices as you install them

What is Plug and Play?

Used on notebook and other mobile computers

Credit card-sized device used to add capabilities to mobile computer

Standards developed by Personal Computer Memory Card International Association (PCMCIA)


What is a PC card?

PortsPorts

What is a port? keyboard

USBUSB

mouse

telephone line in

game port

monitor

svideo out

network

printer (parallel port)

cable TV

speaker

serial port

microphone

telephone line out

FM reception

Used to connect external devices to the system unit

Port is the interface, or point of attachment, to the system unit

Most located on the back of the system unit

PortsPorts

What are the different types of connectors?

PortsPorts

What is a serial port?

serial transmission of data

DB-9 female connector

byte representation for number 3 (00110011) byte

representation for number 5 (00110101)

DB-9 male connector

byte representation for number 1 (00110001)

Transmits one bit of data at a time

Used to connect devices that do not require fast transmission rates• mouse• keyboard• modem

Two common types• 25-pin• 9-pin

PortsPorts

What is a parallel port?

byte representation for number 1byte representation for number 3byte representation for number 5

DB-25 male connector

DB-25 female connector

Connects devices that can transfer more than one bit at a time

Usually used for printers Two newer types

• EPP (Enhanced Parallel Port)

• ECP (Extended Capabilities Port)

IEEE 1284 is a standard that specifies how older and newer peripheral devices transfer data to and from a computer

PortsPorts

What is a universal serial bus port (USB)? Can connect up

to 127 different peripheral devices with a single connector type

Supports newer peripherals

Supports hot plugging and Plug and Play

PortsPorts

How are multiple USB devices connected?

Computer with USB port

Daisy Chain• Devices connected together

outside the system unit in a chain

device 3

device 1

device 4

USB hub• Plugs into the USB port on the

computer

• Contains multiple USB ports

Computer with USB port

device 2

USB hub

device 4

device 2

device 3

device 1

BusesBuses

What is a bus? Electrical channels that allow

various devices inside the computer to communicate with each other

Bus width determines the number of bits transmitted at one time

Word size determines the number of bits the processor can interpret and execute at a given time

Expansion bus

Allows the processor to communicate

with peripheral devices

BusesBuses

What are the two basic types of buses?

System bus

Part of the motherboard that connects the processor

to main memory

BusesBuses

What are the types of expansion buses? Bus type determines

type of expansion card you can add

ISA (Industry Standard Architecture)

Local bus• VESA local bus• PCI (Peripheral

Component Interconnect)

Accelerated Graphics Port (AGP)

Universal serial bus (USB)

PC Card bus

fastest

next fastest

next fastest

slowest

processor

memory

AGP bus slot

PCI bus expansion slots

ISA bus expansion slots

BaysBays

What is a bay?DVD-ROM drive

CD-RW drive

Zip drive

empty drive bay

floppy disk drive

An open area inside the system unit used to install additional equipment

Drive bays

• Used for disk drives

• External drive bay– Also called exposed

drive bay

– Accessible from outside the system unit

• Internal drive bay– Also called hidden

drive bay

– Concealed entirely within the system unit

Some peripheral

devices have an AC adapter

Power SupplyPower Supply

What is a power supply?

Converts alternating

current (AC,115 to 120 volts) to direct current (DC, 5 to 12

volts)

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

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

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

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

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

The Keyboard

What 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

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 Keyboard

What 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

The Keyboard

What 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

Pointing Devices

What 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

Mouse

What 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

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

Mouse

How does a mechanical mouse work?

mouse padmouse pad

ballball

wheel buttonwheel button

mouse buttonsmouse buttons

Mouse

How 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

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 Devices

What are some common mouse operations?

Press and release the secondary mouse button, which usually is the right mouse button

Right-click

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


What 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


What 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


What 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

Voice Input

What 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

Voice Input

How 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

Voice Input

What 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

Digital Cameras

What 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

In digital images the pixel is a tiny square

The greater the number of pixels, the better the quality of the image

Digital Cameras

What 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

Video Input

What 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

video digitizer

Used to capture an individual

frame from an analog video and

then save the picture in a file

Video Input

What 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

Scanners and Reading Devices

What is a scanner? A device that captures data directly from

source documents A source document is the original form of the

data

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


What 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

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


What 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


What is a bar code scanner? Uses laser beams to read

bar codes

Input Devices for Physically Challenged UsersWhy 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

Input Devices for Physically Challenged UsersWhat 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

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

Input Devices for Physically Challenged UsersWhat 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

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 UsersWhat 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

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

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

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

What are Output Devices?

What is an output device? Any hardware component that can convey

information to a user

printer

monitor speakers

Display Devices

What 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

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 Devices

What is a CRT monitor?

CRT monitor screen

cathode ray tube

Display Devices

What 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

Display Devices

What 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

Display Devices

Where 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

800 x 600typically the

standard

Display Devices

What 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

Display Devices

What 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

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 Devices

What 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

Display Devices

What 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

Step 1Step 1Step 2

Step 1Step 2

Step 3

Step 1Step 2

Step 4

Step 3

Step 1Step 2

Step 3

Step 4

Step 5

Step 2

Step 3

Step 4

Step 5

Step 6

Step 1

Display Devices

How 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.

Printers

What 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

Printers

What 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

Printers

What 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

Printers

What 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

Printers

How 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

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

Printers

What 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

Printers

What 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

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

Printers

What 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

Printers

What 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

Speakers and Headsets

What 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 headsetsspeakers

Speakers and Headsets

What 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

Other Output Devices

What 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

Other Output Devices

What 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

special-purpose terminals

intelligent terminals

Terminals

What 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

Terminals

What 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

Terminals

What 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

Terminals

What 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

Output Devices for Physically Challenged UsersWhat 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

Memory Versus Storage

What is storage? The media on which data, instructions, and

information are kept, as well as the devices that record and retrieve these items


How does storage differ from memory?

When you want to work

with a file, you remove it from storage

and place it in memory

When you are finished with the file, you

remove it from memory and return it to

storage

Storage also called secondary storage, auxiliary storage, permanent storage, or mass storage

Storage holds items such as data, instructions, and information for future use

Storage is nonvolatile


What is a storage medium and a storage device?

storage medium

The physical material on which a computer

keeps data, instructions, and

information

storage device

The computer hardware that records and retrieves items to

and from a storage medium

Writing

Process of transferring items from memory to a storage medium

Serves as a source of output


What is reading and writing?

Reading

Process of transferring data, instructions,

and information from a storage medium

into memory

Serves as a source of input


What is access time? The amount of

time it takes the device to locate an item on a disk

Defines the speed of a disk storage device

Memory (RAM)

Compact Disc

Floppy Disk

Tape

Hard Disk

cost

less

exp

ensi

ve

mor

e ex

pens

ive

speed

faster

slower


What is capacity? The number of

bytes (characters) a storage medium can hold

Manufacturers use many terms to define the capacity of storage media

Storage Term Abbreviation Number

of bytes

Kilobyte

Megabyte

Gigabyte

Terabyte

Petabyte

KB

MB

TB

GB

PB

1 thousand

1 million

1 billion

1 trillion

1 quadrillion

Floppy Disks

What is a floppy disk? A portable,

inexpensive storage medium

Consists of a thin, circular, flexible plastic disk with a magnetic coating

Enclosed in a square-shaped plastic shell

Today’s standard disk is 3.5” wide

Floppy Disks

What are the parts of a floppy disk? A thin circular

flexible film is enclosed between two liners

A piece of metal called a shutter covers an opening to the recording surface

shell

shutter

liner

magnetic coating

flexible thin film

metal hub

Floppy Disks

A device that can read from and write on a floppy disk

Most personal computers have a floppy disk drive, in which you insert and remove a floppy disk

What is a floppy disk drive (FDD)?

floppy disk

floppy disk drive

Floppy Disks

How are floppy disk drives designated?

Two floppy drives

drive A

drive B

One floppy drive

drive A

Floppy Disks

How does a floppy disk store data? A type of magnetic media Uses magnetic patterns to store

items such as data, instructions, and information on a disk’s surface

Able to access (read) data from and place (write) data on a magnetic disk any number of times

The read/write head in the floppy disk drive is the mechanism that actually reads items from or writes items on the floppy disk

Floppy Disks

What is a write-protect notch? A small

opening with a cover that you slide up or down

Protects floppy disks from accidentally being erased

notch closed means you

can write on the disk

notch closed means you

can write on the disk

notch open means you

cannot write on the disk

notch open means you

cannot write on the disk

write-protected

not write-protected

Step 6: The read/write heads read data from and write data on the floppy disk.

Step 6

Step 5: A motor positions the read/write heads over the correct location on the recording surface of the disk.

Step 5

Step 4: A motor causes the floppy disk to spin.

Step 4

Step 3: If disk access is a write instruction, the circuit board verifies whether the disk can be written to or not.

Step 3

Step 2: When you initiate a disk access, the circuit board on the drive sends signals to control movement of the read/write heads and the disk.

Step 2

Step 1: When you insert the floppy disk into the drive, the shutter moves to the side to expose the recording surface on the disk.

Step 1

Floppy Disks

How does a floppy disk drive work?

Floppy Disks

What are tracks and sectors? Track: a narrow

recording band that forms a full circle on the surface of the disk

Pie shaped sections break the tracks into small arcs called sectors

A sector can store up to 512 bytes of data

A typical floppy disk stores data on both sides of the disk

sector18 per track

track80 per

side

80 tracks per side X 18 sectors per track X 2 sides per disk X 512 bytes per sector = 1,474,560 bytes

Floppy Disks

What is a cluster? The smallest unit of disk space that stores data Also called an allocation unit 2 to 8 sectors depending on the operating system Each cluster holds data from only one file One file can span many clusters

cluster2 to 8 sectors

Floppy Disks

What is formatting? The process of preparing a

disk for reading and writing Formatting marks bad

sectors as unusable

HiFD™ (High-Capacity

Floppy Disk) drive

Uses a 200 MB HiFD™ disk

Developed by Sony Electronics, Inc.

High-Capacity Disks

What is a high-capacity disk drive? A disk drive that uses disks with capacities of 100 MB

and greater

SuperDisk™ drive

Uses a 120 MB or a 250 MB SuperDisk™

Developed by Imation

Zip® drive

Uses a Zip® disk that can store 100 MB or 250 MB of

data

Developed by Iomega Corporation

built in Zip® drive

Hard Disks

What a hard disk? Consists of several

inflexible, circular platters that store items electronically

Also called a hard disk drive or a fixed disk

A platter is coated with a material that allows items to be recorded magnetically on its surface

The components of a hard disk are enclosed in an airtight, sealed case to protect themHard disk

installed in system unit

Step 4: The head actuator positions the read/write head arms over the correct location on the platters to read or write data

Step 4

Step 2: A small motor spins the platters while the computer is running

Step 2

Step 3: When software requests a disk access, the read/write heads determine the current or new location of the data

Step 3

Step 1: The circuit board controls the movement of the head activator and a small motor

Step 1

Hard Disks

How does a hard disk work?

Hard Disks

What is a cylinder? The location of a

single track through all platters

A single movement of the read/write head arms can read all the platters of data

trackcylinder

Hard Disks

How does access time compare for a hard disk and a floppy disk?

A hard disk’s access time is significantly faster than a floppy disk• The hard disk spins

much faster than a floppy disk

• A hard disk spins constantly, while a floppy disk starts spinning only when it receives a read or write command

Hard disk

Approximately 5 to 11

milliseconds

Floppy disk

84 milliseconds or approximately ½ a

second

Hard Disks

What is a partition? You can divide a

formatted hard disk into separate areas called partitions

Done by issuing a special operating system command

Each partition functions as if it were a separate hard disk drive

instructions, and information to improve data reliability

drive C

Designation for first partition or for a single

partition on the hard disk

drive D

Designation for second partition on the hard

disk

Hard Disks

Windows provides many maintenance and monitoring utilities for a hard disk on the System Tools submenu

What utilities maintain a hard disk drive?

Compact Discs

What is a compact disc (CD)? A flat, round, portable,

metal storage medium that usually is 4.75 inches in diameter and less than one-twentieth of an inch thick

Most personal computers today include some type of compactdisc drive

Also called an optical disc

Available in a variety of formats

CD-ROM

CD-RCD-RW

DVD-ROM

Step 3: Reflected light is deflected to a light-sensing diode, which sends digital signals of 1 to the computer. Absence of reflected light is read as a digital signal of 0.

Step 1: A laser diode shines a light beam toward the compact disc.

Step 2: If light strikes a pit, it scatters. If light strikes land, it is reflected back toward the laser diode.

Compact disc label

Compact disc label

lens lens

prism prism

laser diode

laser diode

Step 1Compact disc

label

lens lens

prism prism

laser diode

laser diode

Items are stored using microscopic pits (indentations) and land (flat areas) that are in the middle layer of the disk

A laser light reads items from the compact disc

Compact Discs

How does a laser read data on a compact disc?

Step 2Compact disc

label

lens lens

prism prism

laser diode

laser diode

pit land

Step 3Compact disc

label

lens lens

prism prism

laser diode

laser diode

Light-sensing

diode

Light-sensing

diode

0 1

pit land

CD-ROMs

What is the storage capacity of a CD-ROM? A typical CD-ROM holds

about 650 MB of data, instructions, and information

Manufactures use CD-ROMs to store and distribute today’s multimedia and other complex software

40X 40 X 150 KB per second =

6,000 KB per second or 6 MB per second

CD-ROMs

What is the data transfer rate of a CD-ROM drive? The time it takes a drive to transmit data, instructions, and

information from the drive to another device Slower CD-ROM drives produce choppy images or sound Drive speed measured relative to original CD-ROM drives

(150 KB per second)

75X 75 X 150 KB per second =

12,250 KB per second or 12.25 MB per second

range of current rates

CD-R and CD-RW

What is a CD-R (compact disc-recordable)? A multisession compact disc onto which you can

record your own items such as text, graphics, and audio

You write on the CD-R using a CD recorder or a CD-R drive and special software

The CD-R drive can read and write both audio CDs and standard CD-ROMs

You cannot erase the disc’s contents

Most CD-ROM drives can read a CD-R

CD-R and CD-RW

What is a CD-RW (compact disc-rewritable)? An erasable disc you can write on multiple times You must have CD-RW software

and a CD-RW drive Discs can be read only by

multiread CD-ROM drives

• Drives that can read audio CDs, data CDs, CD-Rs, and CD-RWs

• Most recent CD-ROM drives are multiread

DVD-ROMs

What is a DVD-ROM (digital video disc-ROM)?

An extremely high capacity compact disc capable of storing from 4.7 GB to 17 GB

You must have a DVD-ROM drive or DVD player to read a DVD-ROM

Looks just like a CD-ROM but data, instructions, and information is stored in a slightly different manner to achieve a higher storage capacity

DVD-ROMs

What are other various DVD formats?

Digital motion picture DVD

Used to play a movie on your television set or view on the

computer

DVD-R (DVD-recordable)A recordable DVD that you can write on once and read

from many times

DVD+RW

A competing technology to DVD-RAM

DVD-RAMA rewritable DVD that allows you to erase and record on

the disc multiple times

Tapes

What is tape? A magnetically coated ribbon of plastic capable of storing large

amounts of data and information at a low cost A tape drive reads from and writes data and information on a tape Older computers used reel-to-reel tape drives A tape cartridge is a small, rectangular, plastic housing for tape

used in today’s tape drives

Tapes

Where is tape used? Used by business and home users to backup personal

computer hard disks Both external and internal tape units for personal

computers Larger computers use tape cartridges mounted in a

separate cabinet called a tape library Three common types of tape drives

Miniature Mobile Storage Media

What is miniature mobile storage media? Handheld

devices use miniature mobile storage media to augment internal storage

Storage CapacityDevice Name Type, Use

Clik! Disk

CompactFlash

Microdrive

SmartMedia

40 MB

2 to 256 MB

1 GB

2 to 128 MB

Cartridge

Digital cameras, notebook computers

Memory Card

Digital cameras, handheld computers, notebook computers, printers, cellular telephones

Memory card

Digital cameras, handheld computers, music players, video cameras

Memory Card

Digital cameras, handheld computers, photo printers, cellular telephones

CHAPTER 4 Hardware applications for Education CHAPTER 4 Hardware applications for Education.

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