C H A P T E R 6 6 6 6 Secondary Storage
CHAPTER 6 66 Secondary Storage. 6 © The McGraw-Hill Companies, Inc. 2002 Objectives 1.Floppy and hard disks 2.Cartridges and disk packs 3.Performance.
Dec 21, 2015
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CH
AP
TE
R
66
6666Secondary
Storage
© The McGraw-Hill Companies, Inc. 2002
66
Objectives
1. Floppy and hard disks
2. Cartridges and disk packs
3. Performance enhancements
4. Compact disks
5. Specialized disks
© The McGraw-Hill Companies, Inc. 2002
66
Secondary Storage
• Save information
• Permanent storage
• Temporary storage
© The McGraw-Hill Companies, Inc. 2002
66
Floppy Disks
• Removable
• Write-protect
• Parts– Tracks– Sectors
© The McGraw-Hill Companies, Inc. 2002
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New Standards
• Zip Disks– 250 MB
• SuperDisks– 120 MB
• HiFD disks– 200 MB
© The McGraw-Hill Companies, Inc. 2002
66
Hard Disks
• Metallic disks
• Fast information
• Read-write heads
• Three types– internal hard disk
– hard-disk cartridge
– hard-disk pack
© The McGraw-Hill Companies, Inc. 2002
66
Human hair
dust particle
fingerprint
smoke particle
disk head
disk surface
© The McGraw-Hill Companies, Inc. 2002
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Internal Hard Disk
• Inside system unit
• Advantage over
floppy disks
• Capacity: 80 gig
© The McGraw-Hill Companies, Inc. 2002
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Hard-disk Cartridges
• Easy removal
• Complements internal
– JAZ from Iomega
– SPARQ from SyQuest
© The McGraw-Hill Companies, Inc. 2002
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Hard-disk Packs
• Removable
• Massive storage capacity
• Common in mainframes
• Resembles stack of vinyl records
© The McGraw-Hill Companies, Inc. 2002
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Performance Enhancements
• Disk caching
• Redundant arrays of inexpensive
disks (RAID)
• File compression and decompression
© The McGraw-Hill Companies, Inc. 2002
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• Compact
• Permanent storage
• Laser beams reflect off pits
• Three types
Optical Disks
© The McGraw-Hill Companies, Inc. 2002
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CD-ROM
• Compact disc-read-only memory
• Not written to
• 650 MB capacity
© The McGraw-Hill Companies, Inc. 2002
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CD-R & CD-RW
• CD-Recordable or WORM
• CD-RW or rewritable optical discs
© The McGraw-Hill Companies, Inc. 2002
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CD-R for Music
• Download from Internet
• Arrange and play music
• Create custom CD-R or
CD-RW
© The McGraw-Hill Companies, Inc. 2002
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DVD
• Digital Versatile Disk or Digital
Video Disk
• Types– DVD-ROM– DVD-R – DVD-RAM or DVD-RW
© The McGraw-Hill Companies, Inc. 2002
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Magnetic Tape
• Fast, direct access
• Sequential access
• Storage and backup
© The McGraw-Hill Companies, Inc. 2002
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A Look to the Future
• Near-field recording devices
• Holographic storage systems
© The McGraw-Hill Companies, Inc. 2002
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