Chapter 08: Secondary Storage
Competencies
(Page 1 of 2)• Distinguish between primary & secondary storage
• Describe the traditional floppy disk and compare it to high capacity floppy disks
• Compare internal hard disks, hard-disk
cartridges, and hard-disk packs
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Competencies
(Page 2 of 2)• Describe ways to improve hard-disk operations,
including disk caching, redundant arrays of
inexpensive disks, and data compression and
decompression
• Discuss the different types of optical disks; mass storage
• Describe solid-state storage, Internet drives, and magnetic tape
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Storage
• Primary storage
– Volatile
– Temporary
• Secondary storage
– Nonvolatile – Permanent
• Secondary storage characteristics
– Media – Capacity
– Storage devices – Access speed
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Secondary Storage Devices
• Most desktop microcomputer systems have floppy disks, hard disks, and optical disk drives
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Traditional Floppy Disk
• Also known as:
– Diskettes – Floppies
– Portable storage media – Floppy disk drives (FDD)
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High Capacity Floppy Disks
Known as a floppy-disk cartridge
• Require special disk drives
• Three well known types
– Zip disks – HiFD disks – SuperDisks
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Hard Disks
• Use thicker, metallic platters for storage
• Faster than a floppy diskette
• Large capacity
• Sensitive instruments
• There are three types of hard disks:
– Internal
– Hard-disk cartridge – Hard-disk pack
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Materials that Cause a Head Crash
• Head crash is a disaster for a hard disk
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Internal Hard Disk
• Located inside system unit
• Known as a fixed disk
• Designated as the C drive
• Advantages over floppies – Access speed
– Capacity
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Optical Disks
• Compact
• Permanent storage
• Laser beams reflect off pits
• Two common types
– CD – DVD
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Compact Disc
• Optical format
• From 650 MB to 1 GB capacity
• Rotation speeds vary
• Types
– Read only: CD-ROM – Write once: CD-R
– Rewriteable: CD-RW
– Picture CDs and Photo CDs
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Digital Versatile Disc
• Digital Versatile Disk or Digital Video Disk (DVD)
• Similar to CDs, but can store more data
• Types
– Read only: DVD-ROM
– Write once: DVD+R; DVD-R
– Rewritable: DVD+RW; DVD-RW; DVD-RAM
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Other Types of Secondary Storage
• Solid-state storage
• Internet hard drives
• Magnetic tape
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Solid-State Storage
• Flash memory cards
– Widely used in notebook computers
– Used to record MP3 music files
• Key chain hard drives
– Key chain flash memory devices
– Connects to a USB port
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Internet Hard Drives
• Known as i-drive or online storage
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Magnetic Tape
• External storage
• Provides sequential access
– Information stored in sequence – Slower than disks which provide
direct access
• Magnetic tape streamers or tape cartridges used by both mainframes and
microcomputers
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