Chapter 73893

8/13/2019 Chapter 73893

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Discovering Computers 2008

Chapter 7

Storage

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Slide # 2

Chapter 7 Objectives

Differentiate between storage devicesand storage media

Describe the characteristics ofmagnetic disks

Describe the characteristics ofa hard disk

Discuss various types of miniature,external, and removable hard disks

Describe the characteristicsof optical discs

Differentiate among CD-ROMs,recordable CDs, rewritable CDs,

DVD-ROMs, BD-ROMs, HD DVD-ROMs, recordable DVDs, and

rewritable DVDs

Identify the uses of tape

Discuss PC Cards, ExpressCardmodules, and the various types of

miniature storage media

Identify uses of microfilm andmicrofiche

Next

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Storage What is storage?

p. 354 - 355 Fig. 7-1 Next

Holds data, instructions, and information for future use

Storage medium is physical material used for storage

Also called secondary storage

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Storage What is capacity?

p. 356 Next

Kilobyte (KB) 1 thousand

Megabyte (MB) 1 million

Gigabyte (GB) 1 billion

Terabyte (TB) 1 trillion

Petabyte (PB) 1 quadrillion

Number of bytes (characters) a storage medium can hold

Exabyte (EB) 1 quintillion

Zettabyte (ZB) 1 sextillion

Yottabyte (YB) 1 septillion

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Storage Medium

(floppy disks, Zip disks,

hard disks, CDs)

Storage How does volatility compare?

p. 356 Next

N o n v o l a t i l e

Storage medium is nonvolatile — contents retained whenpower is off

Contents

retained

Contents

available to user

Memory

(most RAM)

(chips on motherboard)

Screen Display

ON OFF

V o l a t i l e Display

disappears

Data and

instructions

available to user

Display

appears

Data and

instructions erased

Memory is volatile — holds data and instructions temporarily

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Writing

Process of transferring

items from memory

to storage media

Storage What is a storage device?

p. 356 Next

Reading

Process of transferring

items from storage

media to memory

Hardware that

records and

retrieves items

to and from

storage media

Functions as source

of inputCreates output

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Floppy Disk Small files to be transported

Secondary Storage

Primary Storage

Hard Disk

Flash Memory Cardsand USB Flash Drives

CDs and DVDs

Tape

Items waiting to be interpretedand executed by the processor

Operating system, application

software, user data and information

Digital pictures or filesto be transported

Software, backups, movies, music

Backups

Memory (most RAM)

Stores … Transfer rates

Storage What is access time?

p. 357 Fig. 7-4

Time it takes storage device to locate item on storage medium

Next

Time required to deliver item from memory to processor

fastertransfer

rates

slowertransfer

rates

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Magnetic Disks

p. 357 Fig. 7-5 Next

What are tracks and sectors?

Formatting prepares disk for use

Track

is narrow

recording band

that forms fullcircle on disk

Sector

stores up to

512 bytesof data

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Perpendicular recording

Magnetic Disks

What is a hard disk ?


hard disk mountedin system unit

High-capacity storage Consists of several

inflexible, circularplatters that store items

electronically

Components enclosed inairtight, sealed case forprotection

Click to view Web Link,click Chapter 7, Click Web Linkfrom left navigation,then click PerpendicularRecording below Chapter 7

Longitudinal recording

http://www.scsite.com/dc2008cp/ch7/weblink/

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Magnetic Disks

What are characteristics of a hard disk?


Sample Hard Disk Characteristics

Advertised capacity 500 GB

Platters 4

Read/write heads 8Cylinders 16,383

Bytes per second 512

Sectors per track 63

Sectors per drive 973,773,168

Revolutions per minute 7,200

Transfer rate 300 MB per second

Access time 8.5 ms

actualdisk

capacity

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Magnetic Disks

How does a hard disk work?


Step 1. Circuit board controls

movement of head actuator

and a small motor.

Step 2. Small motor spins

platters while

computer is running.

Step 3. When software requests a

disk access, read/write

heads determine current

or new location of data.

Step 4.

Head actuator positionsread/write head arms over

correct location on platters

to read or write data.

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Magnetic Disks

What is a cylinder?


Vertical section of

track through all

platters Single movement

of read/write head

arms accesses all

platters

in cylinder

platter

read/writehead

platter

sides

cylinder

track

sector

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Magnetic Disks

What is a head crash?

p. 360-361 Fig. 7-10 Next

Spinning creates cushion of air that floats read/write head above platter Occurs when read/write head touches platter surface A smoke particle, dust particle, or human hair could render drive unusable Clearance between head and platter is approximately two-millionths of an inch

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Next

Magnetic Disks

What is a disk cache?

p. 361 Fig. 7-11

Portion of

memory that

processor uses

to store

frequently

accessed items

second requestfor data — to hard disk

first requestfor data — to disk cache

Slid # 15

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Next

Magnetic Disks

What is RAID?

p. 362

Redundant Array of Independent Disks

Connects multiple smaller disks into a single unit that

acts as a single large hard disk

Click to view WebLink, click Chapter 7, ClickWeb Link from leftnavigation, then clickRAID below Chapter 7

Slid # 16


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Slide # 16

Next

Magnetic Disks

What is a miniature hard disk?

p. 362 Fig. 7-13

Provide greater storage capacities than flash memory

Smaller than notebook computer hard disks

A pocket hard drive is a self-contained unit

Click to view WebLink, click Chapter 7, ClickWeb Link from leftnavigation, then clickPocket Hard Drivesbelow Chapter 7


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SCSIcontroller supports up to fifteendevices including hard disks, CD

and DVD drives, tape drives, printers,scanners, network cards

SATA (Serial Advanced

Technology Attachment) controller

uses serial signals to transfer data,

instructions, and information

Magnetic Disks

What is a disk controller?

p. 363 - 364 Next

EIDE (Enhanced Integrated Drive

Electronics) controller supports four

hard disks, provides connections for

CD and DVD drives

Chip and circuits that

control transfer ofitems from disk

Slide # 19

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Magnetic Disks

What is online storage?

p. 364 - 365 Fig. 7-15 Next

Others can be authorized

to access your data

Service on Web that provides storage for

minimal monthly fee Files can be accessed from

any computer with Web

access Large files can be downloaded

instantaneously

Click to view WebLink, click Chapter 7, ClickWeb Link from leftnavigation, then clickOnline Storagebelow Chapter 7

Slide # 20


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Magnetic Disks What is a floppy disk ?

p. 365 Fig. 7-16 Next

Portable, inexpensive storage

medium (also called diskette)

Thin, circular, flexible film enclosed

in 3.5” wide plastic shell

Slide # 21

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Push the same buttonto close the tray.

Optical Discs What are optical discs?

p. 366 Fig. 7-17 Next

Most PCs include an

optical disc drive

Flat, round, portable

metal discs made of

metal, plastic, and

lacquer Can be read only or

read/write Insert the disc,label side up.

Push the button to

slide out the tray.

Slide # 22

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Optical Discs

How does a laser read data on an optical disc?

p. 367 Fig. 7-18 Next

laser

diode

laser

diode

prism prism

light-sensingdiode

light-sensingdiode

0 1

lens lenspit land

disc label

Step 1. Laser diode

shines a light

beam toward

disc.

Step 2. If light strikes

a pit, it scatters.

If light strikes a

land, it is

reflected back

toward diode.

Step 3. Reflected light is

deflected to a

light-sensing diode,

which sends digital

signals of 1 tocomputer. Absence

of reflected light is

read as digital

signal of 0.

Slide # 23

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Slide # 23

Optical Discs

How is data stored on an optical disc?

p. 367 Fig. 7-19 Next

Typically stored in

single track Track divided

into evenly

sized sectors that store

items single track

spirals to edge

of disc

disc sectors

Slide # 24

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Optical Discs

How should you care for an optical disc?

p. 368 Fig. 7-20 Next

Slide # 25

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Optical Discs

What is a CD-ROM?

p. 369 Fig. 7-22 Next

Compact disc read-only memory

Cannot erase or modify contents Typically holds 650 MB to 1 GB Commonly used to distribute multimedia and complex software

Click to view WebLink, click Chapter 7, ClickWeb Link from leftnavigation, then clickCD-ROMsbelow Chapter 7

Slide # 26


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Optical Discs

What is the data transfer rate of a CD-ROM drive?

p. 369 Next

75XRanges from

48X to 75X

or faster

75 150 KBps = 11,250 KBps

or 12.25 MBps 1X is 150 KBps

(KB per second)

48X:

48 150 KBps = 7,200 KBps

or 7.2 MBps

Slide # 27

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Slide # 27

Optical Discs

What is a Picture CD?

p. 370 Fig. 7-23 Next

Film developersoffer

Picture CD

service

Can bemodified

using photo

editing software

Stores digitalversions of

roll of film

Step 3. At home, print images

from Picture CD onyour ink-jet photo printer.

At a store, print images to

Picture CD at kiosk.

Step 1. Drop off film to

be developed.

Mark the PictureCD box on the

film-processing

envelope.

Step 2. When you pick up

prints and negatives, a

Picture CD contains

digital images of each

photograph.

Click to view Web Link,click Chapter 7, Click Web Linkfrom left navigation,then click Picture CDs belowChapter 7

Slide # 28


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Optical Discs

What are CD-Rs and CD-RWs?

p. 370 - 371 Next

Must have

CD recorder or CD-R drive

Cannot erase

disc’s contents

CD-R (compact disc-recordable)

— cdisc you can write on once

CD-RW (compact disc-rewritable)

— ceerasable disc you can write on

multiple times

Must haveCD-RW software

and CD-RW driveClick to view WebLink, click Chapter 7, ClickWeb Link from leftnavigation, then clickCD-Rs and CD-RWsbelow Chapter 7

Slide # 29


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Optical Discs

Video: Got Your Video Right Here

Next

CLICK TO START

Slide # 30

http://localhost/var/www/apps/conversion/tmp/scratch_5/07_GotYourVideoHere.wmv

http://localhost/var/www/apps/conversion/tmp/scratch_5/07_GotYourVideoHere.wmv

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Optical Discs

What is a DVD-ROM (digital versatile

disc-ROM or digital video disc-ROM)?

p. 372 Fig. 7-24 Next

Must have DVD-ROM drive or

DVD player to read DVD-ROM Stores databases, music,

complex software, and movies Blu-ray discs have storage

capacity of up to 100 GB

HD-DVD discs have storage

capacity of up to 60 GB UMD can store up to 1.8 GB

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T

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Tape What is tape?

p. 374 Fig. 7-27 Next

Magnetically coated plastic ribbon

capable of storing large amounts

of data at low cost Primarily used for backup

Slide # 33

T

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Tape How is data stored on a tape?

p. 374 Next

Sequential access Unlike direct access — used on hard disks, CDs, and

DVDs — which can locate particular item immediately

Reads and writes data consecutively, like music tape

Slide # 34

PC C d d E C d M d l

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PC Cards and ExpressCard Modules What are PC Cards and ExpressCard Modules?

p. 374 Figs. 7-28 Next

Adds capabilities to computer Credit-card-sized device commonly used in

notebook computers

Slide # 35

Mi i t M bil St M di

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Miniature Mobile Storage Media What is miniature mobile storage media?

p. 375 Fig. 7-29 Next

Storage for small mobile devices

Slide # 36


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Miniature Mobile Storage Media What are common types of flash memory cards?

p. 376 Fig. 7-30 Next

Click to view WebLink, click Chapter 7, ClickWeb Link from leftnavigation, then clickFlash Memory Cards belowChapter 7

CompactFlash Secure Digital xD Picture Card

Memory Stick Memory Stick PRO Duo

Slide # 37



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Miniature Mobile Storage Media

p. 377 Fig. 7-31 Next

How does one type of flash memory card work?

Slide # 38


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Miniature Mobile Storage Media What is a USB Flash Drive?

p. 377 Fig. 7-32 Next

Plugs in a USB port on a

computer or mobile device

Storage capacities up to 64 GB

May eventually make the

floppy disk obsolete

Click to view WebLink, click Chapter 7, ClickWeb Link from leftnavigation, then clickUSB Flash Drivesbelow Chapter 7

Slide # 39



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Miniature Mobile Storage Media What is a smart card?

p. 378 Fig. 7-33 Next

Stores data on microprocessor

embedded in small card

Input, process, output, and

storage capabilities

Click to view WebLink, click Chapter 7, ClickWeb Link from leftnavigation, then clickSmart Cardsbelow Chapter 7

Slide # 40

Mi fil d Mi fi h


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Microfilm and Microfiche What are microfilm and microfiche?

p. 379 Fig. 7-34 Next

Images recorded using

computer output microfilm

recorder

Store microscopic images of

documents on roll or sheet of

film

Microfilm — 100- to

215-foot roll of film

Microfiche — small sheet

of film, usually 4” 6”

Slide # 41

Microfilm and Microfiche

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Microfilm and Microfiche How do life expectancies of various media compare?

p. 379 Fig. 7-35 Next

Microfilm and microfiche have longest life of any storage media

Slide # 42

Putting It All Together

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Putting It All Together What are recommended storage devices for home

users?

p. 380 Fig. 7-37 Next

250 GB hard disk

Online storage

CD or DVD drive

Card reader/writer

USB flash drive

Slide # 43


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Putting It All Together What are recommended storage devices for small

office/home office (SOHO) users?

p. 380 Fig. 7-37 Next

500 GB hard disk

Online storage

CD or DVD drive

External hard drive for backup

USB flash drive

Slide # 44


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Putting It All Together What are recommended storage devices for mobile

users?

p. 380 Fig. 7-37 Next

100 GB hard disk

Online storage

CD or DVD drive

Card reader/writer

Portable hard disk for backup

USB flash drive

Slide # 45


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Putting It All Together What are recommended storage devices for power

users?

p. 380 Fig. 7-37 Next

1.5 TB hard disk

Online storage

CD or DVD drive

Portable hard disk for backup

USB flash drive

Slide # 46


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Putting It All Together What are recommended storage devices for large

business users?

p. 380 Fig. 7-37 Next

Desktop computer

500 GB hard disk

CD or DVD drive

Smart card reader

Tape drive

USB flash drive

Server or Mainframe

Network storage server

40 TB hard disk system

CD-ROM or DVD-ROM server

Microfilm or microfiche

Slide # 47

Summary of Storage

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Summary of Storage

Internal hard disks

External and removable hard disks

Floppy disks

CD-ROMs

Recordable and Rewritable CDs

DVD-ROMs

Blu-ray Discs (BDs)

HD DVD discs

Recordable and Rewritable DVDs

Tape

PC Cards and ExpressCard

modules

Flash memory cards and

USB flash drives

Smart cards, microfilm, andmicrofiche

Documents

Chapter 73893