SECONDARY STORAGE

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Competencies

Distinguish between primary & secondary storage

Discuss the different types of storage media

Describe the traditional floppy disk and the high capacity floppy disks

Describe various types of hard disk devices

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Competencies cont.

Describe ways to improve hard-disk operations

Describe the different types of optical disks

Describe other kinds of secondary storage devices

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Storage

Primary storageVolatile

Temporary

Secondary storageNonvolatile

Permanent

Secondary storage characteristics

Media

Capacity

Storage devices

Access speed

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Secondary Storage Devices

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Floppy Disks

Diskettes

Floppies

Portable storage media

Floppy disk drives (FDD)

Traditional Floppy Disk

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Traditional Floppy Diskette

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Types of Floppies

High capacity

Known as a floppy-disk cartridge

Require special disk drives

Three well known typesZip 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

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Materials that Cause a Head Crash

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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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Hard-Disk Cartridges

Removable hard disks

Used to complement

internal hard disk

Capacities of 10 to 20

GB PC Card Hard Disks

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Hard-Disk Packs

Removable

Massive storage capacity

Common in mainframes

Resembles stack of vinyl records

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Hard-Disk Pack

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Performance Enhancements

Disk caching

Redundant arrays of inexpensive disks (RAID)

File compression and decompression

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Optical Disks

Compact

Permanent storage

Laser beams reflect off pits

Two common typesCD

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

TypesRead only

Write once

Rewritable

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DataPlay

Optical disk

Write once format

Quarter size500 MB capacity

Holds 5 hours of CD-quality sound

Use for storing and playing music files

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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 cardsWidely 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

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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

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A Look to the FutureBlu-Ray Technology

New standard in storage

Blu-RayNew disks use blue laser light instead of the red laser light used in traditional CD players

Disks may ultimately hold Over 30GB on one-sided disks

Over 50GB on two-sided disks

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FAQs

What is the difference between primary storage and secondary storage?

What kinds of floppy disks are available?

What is the C drive of a computer?

When would I use a hard-disk cartridge?

What is the difference between a CD and a DVD?

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Discussion Questions

Discuss three ways to improve the performance of hard disks.

Describe the different types of compact discs.

Describe the different types of DVDs.

What are the advantages and disadvantages of using an Internet hard drive?

Describe solid state technology. Discuss the many uses for key chain flash memory devices.