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Chapter 6Storage
Chapter 6 Objectives
Describe the characteristics ofmagnetic disks
Describe the characteristics ofmagnetic disks
Differentiate between floppy disks and Zip disks
Differentiate between floppy disks and Zip disks
Describe the characteristics ofa hard disk
Describe the characteristics ofa hard disk
Describe the characteristics of optical disks
Describe the characteristics of optical disks
Differentiate among various CD and DVD formats
Differentiate among various CD and DVD formats
Identify the uses of tapeIdentify the uses of tape
Discuss PC Cards and the various typesof miniature mobile storage media
Discuss PC Cards and the various typesof miniature mobile storage media
Identify uses of microfilm and microfiche
Identify uses of microfilm and microfiche
Next
Storage
What is storage?
p. 220 Fig. 6-1 Next
Holds data, instructions, and information for future use Storage medium is physical material used for storage
Also called secondary storage
Storage
What is capacity?
p. 222 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
WritingWritingProcess of transferring Process of transferring
items from memory items from memory to storage mediato storage media
WritingWritingProcess of transferring Process of transferring
items from memory items from memory to storage mediato storage media
Storage
What is a storage device?
p. 222 Next
ReadingReadingProcess of transferring Process of transferring
items from storage items from storage media to memorymedia to memory
ReadingReadingProcess of transferring Process of transferring
items from storage items from storage media to memorymedia to memory
Hardware that Hardware that records and records and
retrieves items retrieves items to and from to and from
storage mediastorage media
Functions as source of input
Creates output
Storage
What is access time?
p. 222
Time it takes storage device to locate item on storage medium
Floppy Disk Small files to be transported
Secondary Storage
Primary Storage
Hard Disk
Flash Memory Cards and USB Flash Drives
CDs and DVDs
Tape
Items waiting to be interpretedand executed by the processor
Operating system, applicationsoftware, user data and information
Digital pictures or files to be transported
Software, backups, movies, music
Backups
Memory (most RAM)
Stores …
Next
Time required to deliver item from memory to processor
fastertransfer
rates
slowertransfer
rates
Magnetic Disks
p. 222 Fig. 6-3 Next
What are tracks and sectors?
Trackis narrow
recording bandthat forms fullcircle on disk
Sector stores up to512 bytes
of data
Formatting prepares disk for use and marks bad sectors as unusable
Magnetic Disks
What is a floppy disk?
p. 223 Next
Portable, inexpensive storage medium (also called diskette)
Thin, circular, flexible film enclosedin 3.5” wide plastic shell
shutter
shell
liner
magneticcoating
flexible thin film
metal hub
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Floppy Disksbelow Chapter 6
Magnetic Disks
What is a floppy disk drive?
p. 223 Fig. 6-4 Next
Floppy disk drive built intoa desktop computer
External floppy disk drive attaches toa computer with a cable
Also called secondary storage
One floppy drive, named drive A
Device that reads from andwrites to floppy disk
Magnetic Disks
What is a write-protect notch?
p. 223 Next
Small opening with a cover that you slide Protects floppy disk from being erased accidentally
hole on thisside meansdisk is high
density
hole on thisside meansdisk is high
density
write-protected
not write-protected
notch closedmeans you
can write onthe disk
notch closedmeans you
can write onthe disk
notch openmeans you
cannot writeon the disk
notch openmeans you
cannot writeon the disk
Magnetic Disks
What is a Zip disk?
p. 223 Fig. 6-5 Next
Magnetic medium that stores 100 MB to 750 MB of data
Zip disks require a Zip drivec—chigh capacity drive that reads from and writes on a Zip disk
Used to back up and to transfer files Backup is duplicate of file, program, or disk
in case original is lostc
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Zip Disks below Chapter 6
Magnetic Disks
What is a hard disk?
p. 224 Fig. 6-6 Next
hard disk installedin system unit
High-capacity storage Consists of several
inflexible, circular platters that store items electronically
Components enclosed in airtight, sealed case for protection
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Hard Disksbelow Chapter 6
Magnetic Disks
What are characteristics of a hard disk?
p. 225 Fig. 6-7 Next
Sample Hard Disk Characteristics
Advertised capacity 120 GB
Platters 3
Read/write heads 6
Cylinders 16,383
Bytes per second 512
Sectors per track 63
Sectors per drive 234,441,648
Revolutions per minute 7,200
Transfer rate 133 MB per second
Access time 8.9 ms
actualdisk
capacity
Magnetic Disks
How does a hard disk work?
p. 225 Fig. 6-8 Next
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 positions read/write head arms over correct location on platters to read or write data.
Video: Install a New Hard Drive
Speed up your computer with a new hard drive
low quality(click to start)
high quality(click to start)
Next
Magnetic Disks
What is a cylinder?
p. 226 Fig. 6-9 Next
Vertical section of track through all platters
Single movement of read/write head arms accesses all plattersin cylinder
platter
read/writehead
platter
sides
cylinder
track
sector
Magnetic Disks
What is a head crash?
p. 226 Fig. 6-10 Next
clearance
read/write head
platter
hair
dustsmoke
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
Next
Magnetic Disks
What is a miniature hard disk?
p. 227 Fig. 6-11
Provide users with greater storage capacities than flash memory Some have a form factor of less than 1 inch Storage capacities range from 2 GB to 100 GB
Magnetic Disks
What are external hard disks and removable hard disks?
p. 227 Fig. 6-12 Next
External hard disk—freestandinghard disk that connects to system unit
Removable hard disk—hard diskthat you insert and removefrom hard disk drive
Used to back up or transfer files
SCSISCSI((SSmallmall CComputeromputer SSystemystem IInterface)nterface)
controller supports up to fifteencontroller supports up to fifteendevices including hard disks, CDdevices including hard disks, CD
and DVD drives, tape drives, printers,and DVD drives, tape drives, printers,scanners, network cardsscanners, network cards
SATASATA (Serial Advanced Serial Advanced Technology AttachmentTechnology Attachment) controller ) controller
uses serial signals to transfer data, uses serial signals to transfer data, instructions, and informationinstructions, and information
Magnetic Disks
What is a disk controller?
p. 227 - 228 Next
EIDEEIDE (EEnhancednhanced IIntegratedntegrated DDrive rive EElectronics) controller supports four lectronics) controller supports four hard disks, provides connections for hard disks, provides connections for
CD and DVD drivesCD and DVD drives
Chip and circuits that Chip and circuits that control transfer of control transfer of items from diskitems from disk
Magnetic Disks
What is online storage?
p. 228 Fig. 6-13 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
Push the same buttonto close the tray.
Optical Discs
What are optical discs?
p. 229 Fig. 6-14 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 toslide out the tray.
Optical Discs
How should you care for an optical disc?
p. 230 Fig. 6-15 Next
Do store thedisc in a jewelbox whennot in use
Do hold a discby its edges
Do noteat, smoke, ordrink neara disc
Do not stack discs
Do not exposethe disc to excessiveheat or sunlight
Do not touchthe undersideof the disc
Optical Discs
What is a CD-ROM?
p. 231 Fig. 6-17 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 Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click CD-ROMsbelow Chapter 6
Optical Discs
What is a Picture CD?
p. 232 Fig. 6-18 Next
Film developers offer
Picture CD service
Can be modified
using photo editing software
Stores digital versions of roll of film
Step 3.At home, print images from Picture CD on your ink-jet photo printer.
At a store, print images to Picture CD at kiosk.
Step 1.Drop off film to be developed. Mark the Picture CD 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 6, Click Web Linkfrom left navigation, then click Picture CDs below Chapter 6
Optical Discs
What are CD-Rs and CD-RWs?
p. 232 Next
Must haveCD recorder
or CD-R drive
Cannot erasedisc’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 softwareand CD-RW drive
Optical Discs
What is a DVD-ROM (digital versatile disc-ROM or digital video disc-ROM)?
p. 233 Fig. 6-19 Next
High capacity disc capable of storing 4.7 GB to 17 GB
Must have DVD-ROM drive or DVD player to read DVD-ROM
Stores databases, music, complex software, and movies
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click DVDs below Chapter 6
Optical Discs
How does a DVD-ROM store data?
p. 233 Fig. 6-20 Next
Two layers of pits are used, lower layer is semitransparent so laser can read through
Some are double-sided Blu-Ray discs currently have a storage capacity of
up to 27 GB
Tape
What is tape?
p. 234 Fig. 6-21 Next
Magnetically coated plastic ribboncapable of storing large amountsof data at low cost
Primarily used for backup
Tape
How is data stored on a tape?
p. 234 - 235 Next
Sequential access
Unlike direct access — used on floppy disks, Zip disks, hard disks, CDs, and DVDs — which can locate particular item immediately
Reads and writes data consecutively, like music tape
PC Cards
What is a PC Card?
p. 235 Figs. 6-22–6-23 Next
Adds capabilities to computer Credit-card-sized device commonly
used in notebook computers
Miniature Mobile Storage Media
What is miniature mobile storage media?
p. 236 Fig. 6-24 Next
Storage for small mobile devices
Smart Media
xD Picture Card
CompactFlash Secure Digital
Memory Stick
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Flash Memory Cardsbelow Chapter 6
Miniature Mobile Storage Media
What is a USB Flash Drive?
p. 236 Fig. 6-25 Next
Plugs in a USB port on a computer or mobile device
Storage capacities up to 4 GB May eventually make the
floppy disk obsolete
Miniature Mobile Storage Media
What is a smart card?
p. 237 Fig. 6-26 Next
Stores data on microprocessor embedded in small card
Input, process, output, and storage capabilities
Click to view Web Link,click Chapter 6, Click Web Linkfrom left navigation, then click Smart Cardsbelow Chapter 6
Microfilm and Microfiche
What are microfilm and microfiche?
p. 238 Fig. 6-27 Next
Images recorded using Images recorded using computer output microfilm recordercomputer output microfilm recorder
Store microscopic images of Store microscopic images of documents on roll or sheet of filmdocuments on roll or sheet of film
Microfilm — 100- to215-foot roll of film
Microfiche — small sheet of film, usually 4” 6”
Microfilm and Microfiche
How do life expectancies of various media compare?
p. 238 Fig. 6-28 Next
Microfilm and microfiche have longest life of any storage media
Putting It All Together
What are recommended storage devices for home users?
p. 239 Fig. 6-29 Next
Home
80 GB hard disk Online storage CD or DVD drive Card reader/writer USB flash drive and/or 3.5-inch
floppy disk drive
Putting It All Together
What are recommended storage devices for small office/home office (SOHO) users?
p. 239 Fig. 6-29 Next
750 MB Zip drive 120 GB hard disk Online storage CD or DVD drive External hard drive for backup USB flash drive and/or 3.5-inch
floppy disk driveSmall Office/Home Office (SOHO)
Putting It All Together
What are recommended storage devices for mobile users?
p. 239 Fig. 6-29 Next
80 GB hard disk Online storage CD or DVD drive Card reader/writer Portable hard disk for backup USB flash drive, and/or 2 GB PC Card hard
disk, and/or 3.5-inch floppy disk driveMobile
Putting It All Together
What are recommended storage devices for power users?
p. 239 Fig. 6-29 Next
CD or DVD drive 300 GB hard disk Online storage Portable hard disk for backup USB flash drive and/or 3.5-inch floppy
disk drive
Power
Putting It All Together
What are recommended storage devices for large business users?
p. 239 Fig. 6-29 Next
Desktop computer160 GB hard diskCD or DVD driveSmart card readerTape driveUSB flash drive and/or 3.5-inch floppy disk drive
Server or MainframeNetwork storage server40 TB hard disk systemCD-ROM or DVD-ROM serverMicrofilm or microfiche
Large Business
Summary of Storage
Floppy disksFloppy disks
Zip disksZip disks
Internal hard disksInternal hard disks
Portable hard disksPortable hard disks
CD-ROMsCD-ROMs
Recordable and rewritable CDsRecordable and rewritable CDs
DVD-ROMsDVD-ROMs
Recordable and rewritable DVDsRecordable and rewritable DVDs
TapeTape
PC CardsPC Cards
Flash memory cardsFlash memory cards
USB Flash DrivesUSB Flash Drives
Microfilm and microficheMicrofilm and microfiche
Chapter 6 Complete
Smart CardsSmart Cards
