1
Chapter 7
Storage
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Chapter 7 Objectives
Memory Versus Storage
3
1
What is storage?
2
v
Media and devices used to store and retrieve data, instructions, and information
Memory Versus Storage
4
1
How does storage differ from memory?
2
v
v
Stores items for future use, rather than temporarily
Storage is nonvolatile, rather than volatile
Memory Versus Storage
5
How does volatility compare?
Memory Versus Storage
6
What is a storage device and a storage
medium?
Memory Versus Storage
7
1
2
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
Memory Versus Storage
8
1
What is access time?
2
v
v
Amount of time it takes device to locate item on disk
Defines speed of disk storage
device
Memory Versus Storage
9
1
What is capacity?
2
v
Number
of bytes (characters) storage medium can hold
Floppy Disks
10
1
2
What is a floppy disk?
v Portable, inexpensive storage medium
v Today’s standard disk is 3.5” wide
Floppy Disks
11
1
What are the parts of a floppy disk?
2
v
Thin, circular, flexible film enclosed between two liners
1
Floppy Disks
12
How are floppy disk drives designated?
Floppy Disks
13
How does a floppy disk
drive work?
Floppy Disks
14
1
What are tracks and sectors?
2
v
v
Track is narrow recording band that forms full circle on disk surface
Sector can store up to 512 bytes of data
Floppy Disks
15
1
2
What is formatting?
v
v
Process of preparing disk for reading and writing
Formatting marks bad sectors as unusable
Floppy Disks
16
1
2
How do you care for a floppy?
v
v
Proper care helps maximize disk’s life
Floppy disk can last at least seven years
Floppy Disks
17
1
What is a write-protect notch?
2
v
v
Small opening with a cover that you slide
Protects floppy disks from being erased accidentally
High-Capacity Disks
18
1
2
What is a high-capacity disk drive?
v Uses disks with capacities of 100 MB and greater
v Primarily used to backup files and transfer files
High-Capacity Disks
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1
What is a backup?
2
v
Duplicate of file, program, or disk that you can use if original is lost, damaged, or
destroyed
Hard Disks
20
1
What is a hard disk?
2
v
High-capacity storage
Consists of several inflexible, circular platters that store items electronically
v Components enclosed in airtight, sealed case for protection
v
Hard Disks
21
How does a hard disk work?
Hard Disks
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1
2
What is a cylinder?
v Location of a single track through all platters
2
v
Single movement of read/write head arms can read same track on a ll platters
Hard Disks
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1
What is a head crash?
2
v
v
Occurs when read/write head touches platter surface
Spinning creates cushion of air that floats read/write head abov e platter
Hard Disks
24
1
What is a disk cache?
2
v
Portion of memory processor uses to store frequently accessed items
Hard Disks
25
1
What is a partition?
2
v
v
Formatted hard disk divided into separate areas called partitions
Each partition functions as if it were a separate hard disk drive
Hard Disks
26
1
What is a removable hard disk?
2
v
Disk drive in which a plastic or metal case surrounds the hard disk so you can
remove it from the drive
v Used for backup or to transfer files
Hard Disks
27
1
2
How does RAID work?
v
Disk system that duplicates data, instructions, and information to improve data reliability
Hard Disks
28
What Windows
utilities
maintain a hard
disk drive?
Hard Disks
29
1
What is an Internet hard drive?
2
v
Service on Web that provides storage to computer users
Most offer
free storage
v Revenues come from advertisers
v
Hard Disks
30
What are advantages of an Internet hard drive?
Compact Discs
31
1
What is a compact disc (CD)?
2
v
Storage medium
v Most PCs include some type of compact disc
drive
v Available in
3
variety of
formats
Compact Discs
32
1
How do you use a compact disc?
2
v
CD drives can read compact discs, including audio discs
Compact Discs
33
How does a laser read data on a compact disc?
Compact Discs
34
1
How is data stored on a compact disc?
2
v
v
Typically stores items in single track
Track divided into evenly sized sectors that store items
Compact Discs
35
1
What is a jewel box?
2
v
Protective case for compact disc
Compact Discs
36
How should you care for a compact disc?
CD-ROMs
37
1
What is a CD-ROM?
2
v
Compact disc that uses same laser technology as audio CDs for recording music
Cannot erase or modify contents
v Typical CD-ROM holds about 650 MB
v Commonly used to distribute software and games
v
CD-ROMs
38
What is the data transfer rate of a CD-ROM drive?
CD-R and CD-RW
39
1
What is a CD-R (compact disc-recordable)?
2
v
v
CD-R and CD-RW
40
41
Compact disc onto which you can record text, graphics, and audio
Write on CD-R using CD burner (recorder) or CD-R drive and special software
1
What is a CD-RW (compact disc-rewritable)?
2
v
Erasable disc you can write on
multiple times
v Must have a CD-RW disc,
CD-RW software,
and CD-RW drive
CD-R and CD-RW
How is an audio
CD created?
4
DVD-ROMs
42
1
What is a DVD-ROM (digital video disc-ROM)?
2
v
High capacity compact disc capable of storing from 4.7 GB to 17 GB
Must have DVD-ROM drive or DVD player to read DVD-ROM
v Primarily used for movies
v Next-generation software will be delivered on DVD
v
DVD-ROMs
43
1
How does a DVD-ROM store data?
2
v
Two layers of pits are used, where lower layer is semitransparent
v Laser can read through it to upper layer
v DVD+RW is a rewritable DVD
Tapes
44
1
What is tape?
2
v
Magnetically coated ribbon of plastic capable of storing large a mounts of data
and information at a low cost
v Primarily used for backup
Tapes
45
What is sequential access versus direct access?
Enterprise Storage Systems
46
1
2
What is an enterprise storage system ?
v Strategy that focuses on availability, protection , organization, and backup of
storage in a company
PC Cards
47
What are uses of PC Cards?
Miniature Mobile Storage Media
48
1
What is miniature mobile storage media?
2
v
Handheld devices use to augment internal storage
Miniature Mobile Storage Media
49
1
How is miniature storage media used?
2
v
Handheld devices, such as players and wallets, read or display c ontents of
miniature storage media such as memory cards
Miniature Mobile Storage Media
50
1
What is a smart card?
2
v
Stores data on thin microprocessor embedded in credit card
Miniature Mobile Storage Media
51
1
What are the types of smart cards?
2
v
Intelligent smart card contains processor and has input, process, output, and
storage capabilities
v Memory card has only storage capabilities
5
Miniature Mobile Storage Media
52
1
What is electronic money?
2
v
Means of paying for goods and services over the Internet
v Also called
e-money or digital cash
Microfilm and Microfiche
53
1
What are microfilm and microfiche?
2
v
v
54
Store microscopic images of documents on a roll or a sheet of film
Images recorded using a computer output microfilm (COM) recorder
Microfilm and Microfiche
How do life expectancies of various media compare?
55
Summary
What are suggested storage devices for the Home user?
56
Summary
What are suggested storage devices for the SOHO user?
57
Summary
What are suggested storage devices for the Mobile user?
58
Summary
What are suggested storage devices for the Large Business user?
59
Summary
What are suggested storage devices for the Power user?
60
Summary of Storage
v
v
v
v
v
v
v
v
v
v
v
v
v
Memory versus storage
Floppy disks
High-capacity disks
Hard disks
Compact discs
CD-ROMs
CD-R and CD-RW
DVD+RW and DVD-ROM
Tapes
Enterprise storage systems
PC Cards
Miniature mobile storage media
Microfilm and microfiche
6
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