Transcript Discovering Computers Fundamentals 2nd Edition

Chapter 6:Storage
Storage
What is storage?
Holds data, instructions, and information for future use
 Storage medium is physical material used for storage

 Also called secondary storage
p. 220 Fig. 6-1
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Storage
What is capacity?

Number of bytes (characters) a storage medium can hold
Kilobyte (KB)
1 thousand
Megabyte (MB) 1 million
p. 222
Gigabyte (GB)
1 billion
Terabyte (TB)
1 trillion
Petabyte (PB)
1 quadrillion
Exabyte (EB)
1 quintillion
Zettabyte (ZB)
1 sextillion
Yottabyte (YB)
1 septillion
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Magnetic Disks
What are tracks and sectors?
Track
is narrow
recording band
that forms full
circle on disk
System
Defrag
Sector
stores up to
512 bytes
of data
Formatting prepares disk for use and marks bad sectors as unusable
p. 222 Fig. 6-3
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Magnetic Disks
What is a hard disk?



hard disk installed
in 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 Link
from left navigation,
then click Hard Disks
below Chapter 6
p. 224 Fig. 6-6
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Magnetic Disks
What are characteristics of a hard disk?
Sample Hard Disk Characteristics
Advertised capacity
Platters
Read/write heads
Cylinders
Bytes per second
Sectors per track
Sectors per drive
Revolutions per minute
Transfer rate
Access time
p. 225 Fig. 6-7
120 GB
3
6
16,383
512
63
234,441,648
7,200
133 MB per second
8.9 ms
actual
disk
capacity
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Magnetic Disks
What are external hard disks and removable hard disks?

Used to back up or transfer files
Removable hard disk—hard disk
that you insert and remove
from hard disk drive
External hard disk—freestanding
hard disk that connects to system unit
p. 227 Fig. 6-12
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Magnetic Disks
What is online storage?




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
Others can be authorized
to access your data
p. 228 Fig. 6-13
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Optical Discs
What are optical discs?



Flat, round, portable
metal discs made of
metal, plastic, and
lacquer
Can be read only or
read/write
Most PCs include an
optical disc drive
p. 229 Fig. 6-14
Push the button to
slide out the tray.
Insert the disc,
label side up.
Push the same button
to close the tray.
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Optical Discs
How should you care for an optical disc?
Do not expose
the disc to
excessive
heat or
sunlight
Do not
eat, smoke, or
drink near
a disc
Do store the
disc in a jewel
box when
not in use
Do not stack discs
Do not touch
the underside
of the disc
p. 230 Fig. 6-15
Do hold a disc
by its edges
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Optical Discs
What are CD-Rs and CD-RWs?
Must have
CD recorder
or CD-R drive
CD-R (compact disc-recordable)
— disc you can write on once
c
Cannot erase
disc’s contents
CD-RW (compact disc-rewritable)
— erasable disc you can write on
multiple times
ce
Must have
CD-RW software
and CD-RW drive
p. 232
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Optical Discs
What is a DVD-ROM (digital versatile
disc-ROM or digital video disc-ROM)?



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 Link
from left navigation,
then click DVDs
below Chapter 6
p. 233 Fig. 6-19
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Miniature Mobile Storage Media
What is a USB Flash Drive?



Plugs in a USB port on a
computer or mobile device
Storage capacities up to 4 GB
May eventually make the
floppy disk obsolete
p. 236 Fig. 6-25
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