Storage4922

Chapter 7 Objectives
Differentiate between storage
and memory
Identify various types of storage
media and storage devices
Explain how a floppy disk
stores data
Identify the advantages of using
high-capacity disks
Describe how a hard disk
organizes data
Identify the advantages of using
an Internet hard drive
Explain how a compact disc
stores data
Understand how to care for a
compact disc
Differentiate between CD-ROMs,
CD-RWs, and DVD-ROMs
Identify the uses of tape
Understand how an enterprise
storage system works
Explain how to use PC Cards
and other miniature storage
media
Identify uses of microfilm and
microfiche
Next
p. 7.2

What Type of Storage Do You Use?
What type of storage do you use for saving
your computer work?
The hard drive only?
A USB drive? Do you watch movies on DVD
or Blu-ray? There are many different
storage methods for computers and other
technology. We'll describe each of the
categories of devices they fall under, the
general mechanics of each and their
physical characteristics.

p. 7. 2 Fig. 7-1
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
Next

p. 7. 3
What is memory?
 A temporary
holding place for
data and
instructions
 Consists of one
or more chips on
the motherboard
 Sometimes called
primary storage
Nonvolatile
memory
Does not lose its
contents when
power is
removed from
the computer
Volatile memory
Loses its contents
when the computer’s
power is turned off
Most memory is
volatile
Next

p. 7. 4
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
Next

How does volatility compare?
State of
Computer
ON
OFF
p. 7. 4 Fig. 7-2
Screen
Display
Volatile
Contents of
Storage
Nonvolatile
Contents of Memory
(most RAM)
Volatile
C6578 print cartridge
$30.25 per cartridge
2 cartridges
$60.50 total due
Contents of
storage
retained when
power is off
Contents of
storage
retained when
power is off
Screen display and contents
of most RAM (memory)
erased when power is off
Screen display and contents
of most RAM (memory)
erased when power is off
Next

p. 7. 4
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
Next

Writing
Process of
transferring items
from memory to a
storage medium
Serves as a
source of output
p. 7. 4
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
Next

p. 7.4 Fig. 7-4
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)
Hard Disk
less expensive more expensive
Compact Disc
Floppy Disk
Tape
cost
faster speed
slower
Next

p. 7. 4 Fig. 7-3
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
GB
TB
PB
1 thousand
1 million
1 billion
1 trillion
1 quadrillion
Next

p. 7. 7
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
Next disk is 3.5” wide

What is a floppy disk drive (FDD)?
p. 7.7 Fig. 7-6
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
floppy
disk
floppy disk
drive
Next

p. 7. 6
Floppy Disks
How are floppy disk drives designated?
Two floppy
drives
drive A
drive B
One floppy drive
drive A
Next

p. 7. 8
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
Next

16
Internal, External, and
Portable Hard Drive Systems

Upward compatible
Able to recognize
newer media
Floppy disk drives are
not upward compatible
p. 7. 7
Floppy Disks
What is density?
 The number of bits
in an area on a
storage medium
 A floppy disk drive
must support that
floppy disk’s
density
 Most floppy disks
today are high
density (HD) with a
capacity of 1.44 MB
Next
Downward compatible
Able to recognize and
use earlier media
Floppy disk drives are
downward compatible

p. 7.8 Fig. 7-8
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
Next disk
sector
18 per track
track
80 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

p. 7.8
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
Next
cluster
2 to 8 sectors

 The process of preparing a
disk for reading and writing
 Formatting marks bad
sectors as unusable
p. 7. 8 Fig. 7-9
Floppy Disks
What is formatting?
Next

p. 7.9
Floppy Disks
How do you care for a floppy?
 A floppy disk can
last at least
seven years
 Proper care
helps to
maximize a
disk’s life
Next
Avoid exposure
to heat and cold
Avoid exposure
to magnetic
fields
Avoid exposure to
contaminants such as
dust, smoke, or salt air
Keep disks in a
storage tray
when not using
them
Never open the
shutter and touch
the disk’s recording
surface

p. 7. 9 Fig. 7-10
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
Next
notch open
means you
cannot write
on the disk
notch open
means you
cannot write
on the disk
notch closed
means you
can write on
the disk
notch closed
means you
can write on
the disk
write-protected
not write-protected

HiFD™
(High-Capacity
Floppy Disk) drive
Uses a 200 MB HiFD™
disk
Developed by Sony
Electronics, Inc.
p. 7.9
High-Capacity Disks
What is a high-capacity disk drive?
 A disk drive that uses disks with capacities of 100 MB
and greater
Next
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
Click to view Web Link
then click Zip® Drives

p. 7.9
High-Capacity Disks
What is a backup?
 A duplicate of a file,
program, or disk that you
can use if the original is
lost damaged, or
destroyed
 High-capacity disks are
often used to
back up
important
data and
information
Next
instructions
data
information

p. 7. 10 Fig. 7-12
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 them
Next Hard 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
p. 7.11 Fig. 7-13
Hard Disks
How does a hard disk work?
Next

p. 7. 11 Fig. 7-14
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
Next
cylinder track
Click to
view
animation

p. 7. 12 Fig. 7-15
Hard Disks
What is a head crash?
 Occurs when a read/write head touches the surface of a
platter
 The platters of the hard disk rotate at a high rate of
speed while the computer is running
 The spinning creates a cushion of air that floats the
read/write head above the platter
Next
hair
read/write head
dust
smoke
platter
gap
Clearance is
approximately
two millionths
of an inch
Clearance is
approximately
two millionths
of an inch

p. 7. 12
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 Next
Hard disk
Approximately 5
to 11
milliseconds
Floppy disk
84 milliseconds or
approximately ½ a
second
Click to view
Web Link
then click
Hard Drives

processor
hard disk
disk cache
first request for data —
to disk cache
p. 7. 12 Fig. 7-16
Hard Disks
What is a disk cache?
 A portion of memory that the processor uses to store
frequently accessed items
Next
second request for data — to hard disk
 A cache
controller
manages cache
and thus
determines
which items
cache should
store

p. 7. 12
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
Next
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

USB port
Used as interface for
many external hard disk
drives
Enhanced Integrated Drive
Electronics (EIDE)
One of the most widely used
controllers
Supports up to four hard disks
p. 7. 13
Hard Disks
What is a disk controller?
 A special purpose chip and
associated electronic
circuits that control the
transfer of data,
instructions, and
information from a disk to
the rest of the computer
 Sometimes called an
interface
 A hard disk controller
(HDC) is the interface for a
hard disk
 May be part of the disk
drive or a separate card
inside the system unit
Next
small computer system
interface (SCSI)
Supports multiple disk drives,
as well as other peripherals
You can daisy chain devices
together

p. 7. 13 Fig. 7-17
Hard Disks
What is a removable hard disk?
 A disk drive in which a plastic or metal case surrounds
the hard disk so you can remove it from the drive
 A popular, reasonably priced, removable hard disk is the
Jaz® disk by Iomega
Next

Click to view
Web Link
then click
Kingston
p. 7. 13
Company on the Cutting
Edge
Kingston Technology
 The world’s leading independent
manufacturer of memory
products of computers,
servers, digital cameras, and
other electronic devices
 Founded by John Tu and
David Sun in 1987
 Markets more than 2,000
products
 Designated as one of the 100 Best
Companies to Work for in the
United States by Fortune
magazine
Click to
view video
Next

p. 7.14 Fig. 7-18
Hard Disks
What is RAID?
 Redundant array of independent disks
 A type of hard disk system that connects several
smaller disks into a single unit that acts like a single
large hard disk
 More reliable than a traditional disk system but quite
expensive
Next

 Level 1, called mirroring, has one backup disk for each disk
 Levels beyond level 1 use a technique called striping, which splits
data, instructions, and information across multiple disks in the
array
p. 7. 14 Fig. 7-19
Hard Disks
How does RAID work?
 RAID duplicates data, instructions, and information to improve data
reliability
Next
Mirroring
(RAID Level 1)
Striping

What utilities
maintain a hard
disk drive?
 Windows
provides
many
maintenance
and
monitoring
utilities for a
hard disk on
the System
Tools
submenu
Click to
view Web
Link then
click Utilities
p. 7. 15 Fig. 7-20
Hard Disks
Next

p. 7. 16 Fig. 7-21
Hard Disks
What is an Internet hard drive?
 A service on the
Web that
provides storage
to computer
users
 Sometimes
called online
storage
 Many offer
storage free of
charge
 Revenues come
Next from advertisers

Allows offsite
backups of data
Others can be
authorized to access
data from your Internet
hard drive
Files can be
accessed from any
computer or device
that has Web
access
Large audio, video,
and graphics files can
be downloaded to an
Internet hard drive
instantaneously
p. 7. 16
Hard Disks
What are advantages of an Internet hard drive?
Next

p. 7. 17
Compact Discs
What is a compact disc (CD)?
Next
 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 compact
disc drive
 Also called an
optical disc
 Available in a
variety of formats
CD-ROM
C D - R
C D - RW
D V D -
R O M

 CD drives can read
compact discs,
including audio
discs
 Most CD drives
include a volume
control button and a
headphone jack
 The drive
designation of a CD
drive usually follows
alphabetically after
that of the hard disk
p. 7. 17 Fig. 7-22
Compact Discs
How do you use a compact disc?
Next
Push button
to slide out
the tray
Push button
to slide out
the tray
Insert disc,
label side up
Insert disc,
label side up
Push the same
button to close
Push the same
button to close
the tray
the tray

Step 3: 2: 1: Reflected If A light laser strikes diode
light a is
pit,
shines a light beam toward
the compact disc.
it scatters. If light strikes
land, it is reflected back
toward the laser diode.
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.
Compact disc
label
lens lens
0 1
prism prism
laser
diode
laser
diode
Step 1
 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
p. 7. 18 Fig. 7-23
Compact Discs
How does a laser read data on a compact disc?
Next
2
pit land
3
Light-sensing
diode
Light-sensing
diode

 A compact disc
typically stores items
in a single track
 It spirals from the
center of the disc to
the edge of the disc
 The track is divided
into evenly sized
sectors in which items
are stored
p. 7. 18 Fig. 7-24
Compact Discs
How is data stored on a compact disc?
Next
Single track spirals
to edge of disc
Compact disc
sectors

p. 7.19 Fig. 7-25
Compact Discs
What is a jewel box?
 A protective
case for a
compact disc
 Place a compact
disc in a jewel
box to protect
data
Next

1: Do not expose
the disc to
excessive heat
2: Doro snuontl iegaht,t .
smoke, or drink
3: Dneoa nr oat dsitsacc.k
discs.
4: Do not touch the
underside of the
5: Ddios cs.tore the
disc in a jewel
box when not in
use.
6: Do hold a disc
by its edges.
p. 7.19 Fig. 7-26
Compact Discs
How should you care for a compact disc?
Next

p. 7. 20
CD-ROMs
What is a CD-ROM?
 A silver-colored compact disc
that uses the same laser
technology as audio CDs for
recording music
 Can contain text, graphics,
audio, and video
 The manufacturer writes, or
records, the contents of
standard CD-ROMs
 You cannot erase or modify
the contents
 A CD-ROM drive or CD-ROM
player is used to read items on
a CD-ROM
Next

then click CD-ROMs
p. 7. 20 Fig. 7-27
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
Next

40X
40 X 150 KB per second =
6,000 KB per second or 6 MB per second
p. 7.20
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)
Next
range of
current rates
75X
75 X 150 KB per second =
12,250 KB per second or 12.25 MB per second

p. 7. 21 Fig. 7-28
CD-ROMs
What is a PhotoCD?
 A compact disc that contains digital photographic
images saved in the PhotoCD format
 Based on a file format developed by Eastman Kodak
 Used by commercial and
professional users
Next
 A multisession disc, which
means you can write
additional data,
instructions, and
information to the disc at a
later time

p. 7. 21
CD-ROMs
Next
What is a Picture CD?
 A single-session disc
offered by Kodak
 Stores digital versions
of photographs for
consumers
 Single-session means
all items are written to
the disc at one time
 Film developers create
the images on the disc
from photographic
negatives at the time a
roll of film is developed
Click to view
Web Link
then click
Picture CDs

p. 7. 22
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
Next
 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

 Discs can be read only by
multiread CD-ROM drives
• Drives that can read
Click to view
Web Link
then click
CD-RWs
p. 7. 22
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
Next
audio CDs, data CDs,
CD-Rs, and CD-RWs
• Most recent CD-ROM
drives are multiread

Step 1: Artist composes a
song and creates a CD.
Step 2a: Song is stored on
audio CD and purchased
by the user.
Step 2b: Song is
compressed and stored on
the Internet.
Step 3a: User inserts audio
CD into CD-ROM drive,
plays song, and copies it to
Step 4: User copies file to
CD-RW disc.
hard disk.
3b: User downloads
as audio file to hard
Step 5: User listens to
song on personal
computer disk.
or removes CD
and listens to song on
portable CD player.
p. 7. 23 Fig. 7-29
CD-R and CD-RW
How is an audio
CD created?
Next
1
2a 2b
3a 3b
4
5

p. 7.24 Fig. 7-30
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
Click to view
video
Next

p. 7. 25 Fig. 7-31
DVD-ROMs
How does a DVD-ROM store data?
 Three storage techniques used to store DVD-ROM data
• Pits are packed closer together to make the disc more dense
• Two layers of pits are used, where the lower layer is
semitransparent so the laser can read through it to the upper
layer
• Some are double-sided, which means you can remove the DVD-ROM
and turn it over to read the other side
Next

Digital motion picture DVD
Used to play a movie on your
television set or view on the
p. 7. 25
DVD-ROMs
What are other various DVD formats?
Next
computer
DVD-R (DVD-recordable)
A recordable DVD that you
can write on once and read
from many times
DVD-RAM
A rewritable DVD that allows
you to erase and record on
the disc multiple times
DVD+RW
A competing technology to
DVD-RAM
Click to view
video

Click to
view Web Link
then click EMC
p. 7. 26
Company on the Cutting
Edge
EMC2
 A provider pf storage
systems for some of the
world’s largest
corporations
 Founded in 1979 by
Richard Egan and Roger
Marino to fill a demand
for add-on memory
boards in the
minicomputer market
Next

Click to view
Web Link
then click
Tapes
p. 7. 26 Fig. 7-32
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
Next

p. 7.26 Fig. 7-33
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
Next

p. 7. 26
Tapes
What is sequential access versus direct access?
Next
Sequential access
Method used for tape
Reading and writing data
consecutively
You must forward or rewind the
tape to a specific point to access
a specific piece of data
Much slower
Utilized most often for long-term
storage and backup
Direct access
Method used for floppy disks,
hard disks, and compact discs
Also called random access
You can locate a particular data
item or file immediately, without
having to move consecutively
through items stored in front of
the desired data item or file
Faster
Used as the primary method of
storage

Next
tape library
CD-ROM
jukeboxes
NAS NNNAAASSS device
dddeeevvviiiccceee Internet backup
RAID
SAN
servers
p. 7.27 Fig. 7-34
Enterprise Storage
Systems
What is an enterprise storage system?
 A strategy that
focuses on the
availability,
protection ,
organization,
and backup of
storage in a
company
 Goal is to
consolidate
storage so
operations run
as efficiently as
possible

Server
CD-ROM jukebox
RAID system
Stores data, information,
and instructions need by
users on the network
Holds hundreds of CD-ROMs
that can contain Tape application
library
Ensures that data is not lost if
one drive fails
programs and data
A high-capacity tape system
that works with multiple tape
Also called a CD-ROM server
cartridges for storing
backups of data, information,
Internet backup
and instructions
Stores data, information,
and instructions on the
Network-attached storage
(NAS) device
Web
An easy way to add additional
hard disk space to the network
p. 7. 27
Enterprise Storage
Systems
What storage techniques are used in an
enterprise system?
Next
Storage area network (SAN)
A high-speed network that
connects storage devices

p. 7. 28
Enterprise Storage
Systems
How do organizations handle storage?
Next
Enterprise storage
system managed in
house
Data warehouse
A huge database system
that stores and manages
historical and current
transaction data
Storage management
offloaded to an outside
organization or online
Web service

then click PC Cards
p. 7. 28 Fig. 7-35
PC Cards
What is a PC Card?
 A thin, credit card-sized device
 Fits into a PC Card slot on a notebook other personal
computer
 Different types and sizes add storage, additional
memory, communications, and sound capabilities to a
computer
Next

p. 7. 28 Fig. 7-36
PC Cards
What are the uses of PC Cards?
 Three types of PC Card
 Advantage of a PC Card for storage is portability
between systems
Next

p. 7. 28 Fig. 7-37
Miniature Mobile Storage
Media
What is miniature mobile storage media?
 Handheld
devices use
miniature
mobile
storage
media to
augment
internal
storage
Next
Device Name Storage Capacity 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
computers, music players,
video cameras
Memory Card
computers, photo printers,
cellular telephones

p. 7. 29 Fig. 7-38
Media
How is miniature storage media used?
 Handheld devices, such
as players and wallets,
read or display the
contents of miniature
storage media such as
memory cards
Next

p. 7. 29 Fig. 7-39
Media
What is a smart card?
 Stores data on a thin
microprocessor embedded
in the card
 Similar in size to a credit
card
 Read smart card with a
specialized card reader
 Information on the smart
card can be read and
updated
Next

Store data such as
photographs, music, books,
and video clips
p. 7. 29
Media
What are the types of smart cards?
 Intelligent smart
card contains a
processor and
has input,
process, output,
and storage
capabilities
 Memory card has
only storage
capabilities
Next
Store a prepaid dollar amount
that is updated when the card is
used
Store patient records,
vaccination data, and other
healthcare information
Store tracking information such
as customer purchases or
employee attendance

p. 7. 29
Media
What is electronic money?
 A means of
paying for goods
and services
over the Internet
 Also called
digital cash
Next
A bank issues
unique digital
cash numbers
that represent an
amount of money
When you
purchase digital
cash, the amount
of money is
withdrawn from
your bank
account
To use the card
you swipe it
through a card
reader

p. 7. 30 Fig. 7-40
Microfilm and Microfiche
What are microfilm and microfiche?
 Store microscopic images of
documents on roll or sheet film
 Images recorded onto film using
a computer output microfilm
(COM) recorder
 Images can only be read with a
microfilm or microfiche reader
Next
Microfiche
Uses a small sheet
of film, usually
about four inches
by six inches
Microfilm
Uses a 100- to 215-
foot roll of film

p. 7.30 Fig. 7-41
Microfilm and Microfiche
How do life expectancies of various media
compare?
 Microfilm and microfiche are inexpensive
and have the longest life of any storage
medium
Next

Home Mobile 3.5-inch HD floppy disk drive Large Business
75 GB hard disk
DVD-ROM drive
CD-RW drive
Microfilm or microfiche
Smart card reader
RAID
Tape drive
Enterprise storage system
3.5-inch HD floppy disk drive
DVD-ROM drive
CD-RW drive
75 GB hard disk
Internet hard drive
2 GB Jaz® drive
1 GB PC Card hard disk
10 GB hard disk
Internet hard drive
DVD-ROM drive or 40X CD-ROM drive
40 GB hard disk
Internet hard drive
DVD-ROM drive
CD-RW drive
2 GB Jaz® drive
Mobile
p. 7. 31 Fig. 7-42
Summary
What are suggested storage devices for
computer users?
Next
250 MB Zip® drive
30 GB hard disk
Internet hard drive
DVD-ROM drive
CD-RW drive
Small Office/Home Office
Power

Summary of Storage
 Memory versus storage
 Floppy disks
 High-capacity disks
 Hard disks
 Compact discs
 CD-ROMs
 CD-R and CD-RW
 DVD-ROMs
 Tapes
 Enterprise storage systems
 PC Cards
 Miniature mobile storage media
 Microfilm and microfiche
Next

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