Copyright 2003 The McGraw-Hill Comp anies, Inc. Copyright 2003 The McGraw-Hill Companies, Inc. 1 puting ESSENTIALS C H A P T E R 6 6 Secondary Storage puting ESSENTIALS
Computing ESSENTIALS CHAPTER Copyright 2003 The McGraw-Hill Companies, Inc.Copyright 2003 The McGraw-Hill Companies, Inc. 1 66 Secondary Storage computing.
Mar 31, 2015
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Copyright 2003 The McGraw-Hill Companies, Inc.
Copyright 2003 The McGraw-Hill Companies, Inc.
1
computing ESSENTIALS
CH
AP
TE
R 6666Secondary
Storage
computing ESSENTIALS
Copyright 2003 The McGraw-Hill Companies, Inc.
2
Competencies
Different types of media
Floppy disks
Hard disks
Performance enhancements
Optical disks
Specialized media
computing ESSENTIALS
Copyright 2003 The McGraw-Hill Companies, Inc.
3
Secondary Storage
Stores information
Non-volatile, permanent storage
Characteristics
Media
Capacity
Access time
computing ESSENTIALS
Copyright 2003 The McGraw-Hill Companies, Inc.
4
Types of Storage Media
Types widely used today
Floppy disks
Hard disks
Optical disks
Magnetic tape
computing ESSENTIALS
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5
Floppy Disks
Portable and removable Flat circular Mylar media
Magnetic charge on metal oxide film coating
Standard 2HD 1.44 MB Parts
Tracks Sectors
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High Capacity Floppy Disks
Floppy disk cartridges
Zip Disks
250 MB
SuperDisks
120 MB
HiFD disks
200 MB
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Hard Disks Metallic disks Fast retrieval, greater capacity Read/write heads ride cushion of
air .000001” thick
Three types
Internal hard disk
Hard-disk cartridge
Hard-disk pack
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computing ESSENTIALS
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Internal Hard Disk
Inside system unit
Non-removable or portable
Great capacity
Over 100 Gigabytes
Fast access speed
computing ESSENTIALS
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10
Hard-disk Cartridges
Portable, removable
Complement internal
hard drive
JAZ from Iomega
SPARQ from
SyQuest
PC Card Hard Disks
Laptop computers
computing ESSENTIALS
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11
Hard-disk Packs
Used in mainframes
Removable
Resemble stack of vinyl
records
Multiple read/write heads
Massive storage capacity
Fast access time
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12
Performance Enhancements
Improving performance of hard disks
Disk caching
Redundant Arrays of Inexpensive Disks
(RAID)
File compression and decompression
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Very large capacity Up to 17 gigabytes
Use reflected light projected by a laser Lands and Pits represent 1’s and 0’s Formats
Compact Disk (CD) Digital Versatile Disk (DVD) DataPlay
Optical Disks
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14
Compact Disks
Widely used format today Can store from 650 MB to 1 GB Rotational speed = data transfer time Types of CDs
CD-ROM CD-R CD-RW
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15
CD-ROM
Compact Disc-Read Only Memory
Cannot be written to or erased
Similar to commercial music CDs
Used often to distribute large databases or
references
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CD-R & CD-RW
CD-Recordable
Written to once
Custom made music CDs
CD-ReWritable
Erasable CD
Ideal for multimedia presentations
computing ESSENTIALS
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17
DVD
Digital Versatile Disk
Rapidly replacing CDs
Higher capacity
17 times the capacity of a CD
computing ESSENTIALS
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18
DVD Types
DVD types DVD-ROM
Read only memory DVD-R
Recordable DVD-RAM or DVD-RW
Competing rewritable formats
computing ESSENTIALS
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DataPlay
Optical write-once format
Similar to CD-R
Size of a quarter
Used for special applications
Storing digital photographs
Storing music for portable players
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20
Other Secondary Storage Types Complement other secondary storage devices
Specialized device types
Magnetic tape
Internet hard drives
Solid state storage
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21
Magnetic Tape
Sequential access
Commonly used for backing-up data
Very large capacity
Types of magnetic tape
Tape cartridges
Magnetic tape reels
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22
Magnetic Tape Types Tape cartridges
Backup tape for microcomputer Capacities range from 120 MB to 5 GB Digital audio tape (DAT)
Tape reels Minicomputer and mainframe 1/2 inch wide and 1/2 mile long Stores 1600 to 6400 cpi
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Internet Hard Drive and Solid State Internet hard drive
Free or low-cost storage on the Web Access information from any location Access time is greater
Solid-state storage No moving parts Flash memory cards
computing ESSENTIALS
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24
A Look to the Future
Blue laser light optical devices Aimed more accurately Can increase storage capacity to 27 GB
per standard optical disk New players will likely play both
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25
computing ESSENTIALS
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