Transcript CGS 1000 - Hillsborough Community College

CGS 1000
Introduction to Computers and
Technology
Fall 2006
Discovering Computers Fundamentals,
Third Edition
Topics
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Chapter 6
Class Activity
EX 81 to 111
 PPT 4 to PPT 65
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Discovering Computers Fundamentals,
Third Edition
Topics Covered
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Chapter 5 Objectives
Defined Input
Discussed about
Keyboard
 Mouse
 Voice Input
 Touch Screen
 Voice input
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
Digital Cameras
Discovering Computers Fundamentals,
Third Edition
Chapter 6 Objectives
Describe the characteristics of
magnetic disks
Differentiate among various CD and
DVD formats
Describe the characteristics of
a hard disk
Identify the uses of tape
Differentiate between floppy disks
and Zip disks
Discuss PC Cards and the various types
of miniature mobile storage media
Describe the characteristics of optical
disks
Identify uses of microfilm and
microfiche
Discovering Computers Fundamentals,
Third Edition

What is storage?
Storage
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Holds data, instructions, and information for future use
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Storage medium is physical material used for storage
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Also called secondary storage
Discovering Computers Fundamentals,
Third Edition

What is capacity?

Storage
Number of bytes (characters) a storage medium can hold
Kilobyte (KB)
1 thousand
Megabyte (MB) 1 million
Gigabyte (GB)
1 billion
Terabyte (TB)
1 trillion
Petabyte (PB)
1 quadrillion
Exabyte (EB)
1 quintillion
Zettabyte (ZB)
1 sextillion
Yottabyte (YB)
1 septillion
Discovering Computers Fundamentals,
Third Edition
Storage

What is a storage device?
Reading
Process of transferring
items from storage
media to memory
Hardware that
records and
retrieves items
to and from
storage media
Functions as source
of input
Writing
Process of transferring
items from memory
to storage media
Creates output
Discovering Computers Fundamentals,
Third Edition
Storage

What is access time?
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Time it takes storage device to locate item on storage
medium
Time required to deliver item from memory to
processor
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks
What
are tracks and sectors?
Sector
stores up to
512 bytes
of data
Track
is narrow
recording band
that forms full
circle on disk
Formatting prepares disk for use and marks bad sectors as unusable
Discovering Computers Fundamentals,
Third Edition

Magnetic Disks hard disk installed
What is a hard disk?
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High-capacity storage
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Consists of several
inflexible, circular
platters that store items
electronically
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Components enclosed in
airtight, sealed case for
protection
Discovering Computers Fundamentals,
Third Edition
in system unit
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
120 GB
3
6
16,383
512
63
234,441,648
7,200
133 MB per second
8.9 ms
actual
disk
capacity
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks

How does a hard disk work?
Step 3.
When software requests a
disk access, read/write
heads determine current
or new location of data.
Step 2.
Small motor spins
platters while
computer is running.
Step 4.
Head actuator positions
read/write head arms over
correct location on platters
to read or write data.
Step 1.
Circuit board controls
movement of head actuator
and a small motor.
Discovering Computers Fundamentals,
Third Edition
Magneticplatter
Disks

What is a cylinder?
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Vertical section
of track through
all platters
Single movement
of read/write
head arms
accesses all
platters
in cylinder
track
sector
read/write
head
platter
sides
cylinder
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks

What is a head crash?
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Occurs when read/write head touches platter surface
Spinning creates cushion of air that floats read/write head above platter
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Clearance between head and platter is approximately two-millionths of an inch
A smoke particle, dust particle, or human hair could render drive unusable
hair
read/write head
dust
smoke
clearance
platter
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks

What is a miniature hard disk?
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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 120 GB
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks
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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
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks

What is a disk controller?
Chip and circuits that
control transfer of
items from disk
SATA (Serial Advanced
Technology Attachment) controller
uses serial signals to transfer data,
instructions, and information
SCSI
EIDE (Enhanced Integrated Drive (Small Computer System Interface)
controller supports up to fifteen
Electronics) controller supports four
devices including hard disks, CD
hard disks, provides connections for
and DVD drives, tape drives, printers,
CD and DVD drives
scanners, network cards
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks
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What is online storage?
Files can be accessed from
any computer with Web
access
Service on Web that provides
storage for minimal monthly
fee
Large files can be downloaded
instantaneously
Others can be authorized to
access your data
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks

What is a floppy disk?

shutter
Portable, inexpensive storage
medium (also called diskette)
shell
liner
magnetic
coating
Thin, circular, flexible film enclosed
in 3.5” wide plastic shell
metal hub
flexible thin film
Discovering Computers Fundamentals,
Third Edition
Magnetic Disks

What is a floppy disk drive?
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Device that reads from and writes to floppy disk
 One floppy drive, named drive A
Also called secondary storage
Floppy disk drive built into
a desktop computer
Discovering Computers Fundamentals,
Third Edition
External floppy disk drive
attaches to a computer with
a cable
Magnetic Disks
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What is a Zip disk?
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Magnetic medium that stores 100 MB
to 750 MB of data
Used to back up and to transfer files
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Backup is duplicate of file, program, or
disk in case original is lost
c
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Zip disks require a Zip drive-high
capacity drive that reads from and
writes on a Zip disk
Discovering Computers Fundamentals,
Third Edition
Questions?
Discovering Computers Fundamentals,
Third Edition