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SECONDARY STORAGE
2
Storage
Primary storageVolatile
Temporary
Secondary storageNonvolatile
Permanent
Secondary storage characteristics
Media
Capacity
Storage devices
Access speed
3
Secondary Storage Devices
4
Floppy Disks
Diskettes
Floppies
Portable storage media
Floppy disk drives (FDD)
Traditional Floppy Disk
5
Traditional Floppy Diskette
6
Types of Floppies
High capacity
Known as a floppy-disk cartridge
Require special disk drives
Three well known typesZip disks ,100MB, 250MB, 750MB
HiFD disks, 200MB, 720MB
SuperDisks, 120MB, 240MB
7
Hard Disks
Use thicker, metallic platters for storage
Faster than a floppy diskette
Large capacity
Sensitive instruments
8
Materials that Cause a Head Crash
9
Internal Hard Disk
Located inside system unit
Known as a fixed disk
Designated as the C drive
Advantages over floppies
Access speed
Capacity
10
Hard-Disk Cartridges
Removable hard disks
Used to complement
internal hard disk
Large capacity
PC Card Hard Disks
11
Hard-Disk Packs
Removable
Massive storage capacity
Common in mainframes
12
Hard-Disk Pack
13
Performance Enhancements
Disk caching
Redundant arrays of inexpensive disks (RAID)
File compression and decompression
14
Optical Disks
Compact
Permanent storage
Laser beams reflect off pits
Two common typesCD
DVD
15
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
TypesRead only
Write once
Rewritable
17
DataPlay
Optical disk
Write once format
Quarter size500 MB capacity
Holds 5 hours of CD-quality sound
Use for storing and playing music files
18
Other Types of Secondary Storage
Solid-state storage
Internet hard drives
Magnetic tape
19
Solid-State Storage
Flash memory cardsWidely used
Can be used to record MP3 music files
Key chain hard drives Key chain flash memory devices
Connects to a USB port
20
Internet Hard Drives
21
Magnetic Tape
External storage
Provides sequential accessInformation stored in sequence
Slower than disks which provide direct access
Magnetic tape streamers or tape cartridges used by both mainframes and microcomputers
The End of Chapter 8