Chapter 7Storage
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
Chapter 7 Objectives
p. 7.2
Next
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
Memory Versus Storage
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
Memory Versus Storage
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
Memory Versus Storage
How does volatility compare?
p. 7. 4 Fig. 7-2
State of Computer
ON
OFF
Screen DisplayVolatile
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
Memory Versus Storage
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
Memory Versus Storage
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
Memory Versus Storage
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
Next
p. 7. 4 Fig. 7-3
Memory Versus Storage
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
Next
p. 7.7
Technology Trailblazer
Al Shugart Joined IBM as a
customer engineer in 1951
Supervised a team in 1967 responsible for developing a removable, portable data storage device
Founded Shugart Associates in 1973 and Seagate Technology in 1979
Click to view Web Linkthen click Al Shugart
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 disk is 3.5” wideNext
p. 7.6 Fig. 7-5
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
Next
Click to view Web Linkthen click Floppy Disks
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
What is a floppy disk drive (FDD)?
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
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
p. 7. 7 Fig. 7-7
Floppy Disks
How does a floppy disk drive work?
Next
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 disk
Next
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
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
cluster2 to 8 sectors
p. 7. 8 Fig. 7-9
Floppy Disks
What is formatting?
Next
The process of preparing a disk for reading and writing
Formatting marks bad sectors as unusable
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 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
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 Linkthen 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
data
instructions
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 themNext 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
trackcylinder
Click to viewanimation
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
dustsmoke
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 Linkthen click Hard Drives
processor
hard disk
disk cache
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
processor
hard disk
disk cache
second request for data — to hard disk
first request for data — to disk cache
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
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 magazineClick to
view video
Next
Click to view Web Link then click Kingston
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
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
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. 15 Fig. 7-20
Hard Disks
Next
Windows provides many maintenance and monitoring utilities for a hard disk on the System Tools submenu
Click to view Web Link then click Utilities
What utilities maintain a hard disk drive?
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 from advertisers
Next
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 compactdisc drive
Also called an optical disc
Available in a variety of formats
CD-RO
M
CD-RCD-RW
DVD-ROM
p. 7. 17 Fig. 7-22
Compact Discs
How do you use a compact disc?
Next
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
Push button to slide out
the tray
Push button to slide out
the tray
Insert disc, label side upInsert disc,
label side up
Push the same button to close
the tray
Push the same button to close
the tray
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
p. 7. 18 Fig. 7-23
Compact Discs
How does a laser read data on a compact disc?
Next
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
p. 7. 18 Fig. 7-24
Compact Discs
How is data stored on a compact disc?
Next
Compact disc sectors
Single track spirals to edge of disc
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. 7.19 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
p. 7.19 Fig. 7-26
Compact Discs
How should you care for a compact disc?
Next
1: Do not expose the disc to excessive heat or sunlight.
2: Do not eat, smoke, or drink near a disc.3: Do not stack discs.
4: Do not touch the underside of the disc.5: Do store the disc in a jewel box when not in use.
6: Do hold a disc by its edges.
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
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
Click to view Web Link then click CD-ROMs
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
75X 75 X 150 KB per second =
12,250 KB per second or 12.25 MB per second
range of current rates
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
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
What is a Picture CD?
Click to view Web Linkthen 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
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
Click to view Web Linkthen click CD-RWs
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
Step 5: User listens to song on personal computer or removes CD and listens to song on portable CD player.
11
2a 2b
1
2a 2b
3a 3b
1
2a 2b
3a 3b
4
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 the hard disk.
Step 3b: User downloads song as audio file to hard disk.
p. 7. 23 Fig. 7-29
CD-R and CD-RW
How is an audioCD created?
Next
Step 1: Artist composes a song and creates a CD.
Step 4: User copies file to CD-RW disc.
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
p. 7. 25
DVD-ROMs
What are other various DVD formats?
Next
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
Click to view video
p. 7. 25
Technology Trailblazer
Mark Dean Designs microprocessors,
improvements in architecture, and hardware innovations for IBM
First African-American to receive an IBM Fellowship, the company’s highest technical ranking
Inducted into the National Inventor's Hall of Fame
Next
Click to view Web Linkthen click Mark Dean
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 Linkthen click EMC
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
Click to view Web Linkthen click Tapes
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
NAS device Internet backupNAS deviceNAS device
CD-ROM jukeboxes
Internet backup
tape library
NAS device
CD-ROM jukeboxes
Internet backup
RAID
SAN
servers
tape library
NAS device
CD-ROM jukeboxes
Internet backup
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
Network-attached storage (NAS) device
An easy way to add additional hard disk space to the network
Internet backup
Stores data, information, and instructions on the
Web
CD-ROM jukebox
Holds hundreds of CD-ROMs that can contain application
programs and data
Also called a CD-ROM server
RAID system
Ensures that data is not lost if one drive fails
Server
Stores data, information, and instructions need by
users on the networkTape library
A high-capacity tape system that works with multiple tape
cartridges for storing backups of data, information,
and instructions
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
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
Click to view Web Linkthen click PC Cards
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
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
p. 7. 29 Fig. 7-38
Miniature Mobile Storage 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
Miniature Mobile Storage 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
Miniature Mobile Storage 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
Miniature Mobile Storage 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
Large BusinessHome Mobile
Small Office/Home Office Power
3.5-inch HD floppy disk driveDVD-ROM driveCD-RW drive75 GB hard diskInternet hard drive 2 GB Jaz® drive
Large Business3.5-inch HD floppy disk drive75 GB hard diskDVD-ROM driveCD-RW driveMicrofilm or microficheSmart card readerRAIDTape driveEnterprise storage system
Small Office/Home Office
3.5-inch HD floppy disk drive40 GB hard diskInternet hard driveDVD-ROM driveCD-RW drive2 GB Jaz® drive
3.5-inch HD floppy disk drive1 GB PC Card hard disk10 GB hard diskInternet hard driveDVD-ROM drive or 40X CD-ROM drive
Mobile
p. 7. 31 Fig. 7-42
Summary
What are suggested storage devices for computer users?
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Large Business
Power
Home 3.5-inch HD floppy disk drive250 MB Zip® drive30 GB hard diskInternet hard driveDVD-ROM driveCD-RW drive
Large BusinessHome Mobile
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
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Chapter 7 Complete