Computers 2011 Discovering

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Living in a Digital World

Discovering

Computers 2011

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Objectives Overview

Differentiate between storage devices and storage media

Describe the characteristics of an internal hard disk including capacity, platters, read/write heads, cylinders, sectors and tracks, revolutions per minute,

transfer rate, and access time

Discuss the purpose of network attached storage devices, external and removable hard disks, and hard disk controllers

Describe the various types of flash memory storage

Discovering Computers 2011: Living in a Digital World Chapter 7

See Page 351 2

for Detailed Objectives

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Objectives Overview

Describe cloud storage and explain its

advantages

Describe the

characteristics of optical discs

Differentiate among various types of optical discs: CDs, archive discs

and Picture CDs, DVDs, and Blu-ray Discs

Identify the uses of tape, magnetic stripe cards, smart cards, microfilm

and microfiche, and enterprise storage

Discovering Computers 2011: Living in a Digital World 3

See Page 351

for Detailed Objectives

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Storage

Storage holds data, instructions, and information for future use

A storage medium is the physical

material on which a computer keeps data, instructions, and information

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Storage

Pages 352 – 353

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Storage

• Capacity is the number of bytes a storage medium can hold

Page 354 6 Figure 7-2

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Storage

• A storage device is the computer hardware that records and/or retrieves items to and from

storage media

Page 354

Reading is the process of transferring items from a storage medium into memory

Writing is the process of

transferring items from

memory to a storage

medium

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Storage

• Access time measures:

– The amount of time it takes a storage device to locate an item on a

storage medium

– The time required to deliver an item from memory to the

processor

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Hard Disks

• A hard disk contains one or more inflexible, circular platters that use magnetic particles to store data, instructions, and information

Page 355

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Hard Disks

• Hard disks can store data using longitudinal

recording or perpendicular recording

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Hard Disks

• Characteristics of a hard disk include:

Page 357

Capacity Platters Read/Write Heads

Cylinders Sectors and Tracks

Revolutions per Minute Transfer

Rate Access Time

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Hard Disks

• Formatting is the process of dividing the disk into tracks and sectors so that the operating system can store and locate data and information on the disk

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Hard Disks

Page 358

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Hard Disks

• The hard disk arms move the read/write

head, which reads items and writes items in the drive

– Location often is referred to by its cylinder

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Hard Disks

• A head crash occurs when a read/write head touches the surface of a platter

• Always keep a backup of your hard disk

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Hard Disks

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Hard Disks

• RAID (redundant array of independent disks) is a group of two or more integrated hard disks

• A network attached storage (NAS) device is a server connected to a network with the sole purpose of providing storage

Page 360

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Hard Disks

An external hard disk is a separate free- standing hard disk that connects to your computer with a cable or wirelessly

A removable hard disk is a hard disk that you insert and remove from a drive

Internal and external hard disks are available in miniature sizes (miniature hard disks)

Pages 360 – 361 18 Figures 7-14 – 7-15

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Hard Disks

• A disk controller consists of a special-purpose chip and electronic circuits that control the transfer of data,

instructions, and information from a disk to and from the system bus and other components of the computer

Pages 361 - 362

SATA EIDE SCSI SAS

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Flash Memory Storage

• Flash memory chips are a type of solid state media (contains electronic components) and contain no moving parts

• Solid state drives (SSDs) have several advantages over magnetic hard disks:

Pages 362 - 363 20

Faster access time Faster transfer rates Generate less heat and

consume less power Last longer

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Flash Memory Storage

Page 363

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Flash Memory Storage

• A memory card is a removable flash memory

device that you insert and remove from a slot in a computer, mobile device, or card reader/writer

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CompactFlash (CF)

Secure Digital (SD)

Secure Digital High Capacity

(SDHC)

microSD

microSDHC xD Picture

Card Memory Stick Memory Stick

Micro (M2)

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Flash Memory Storage

Pages 364 – 365 Figures 7-18 – 7-19

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Flash Memory Storage

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Flash Memory Storage

• USB flash drives plug into a USB port on a computer or mobile device (512 MB-100 GB)

Page 367

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Flash Memory Storage

• An ExpressCard module is a removable device that fits in an

ExpressCard slot

• Developed by the PCMCIA

• Commonly used in notebook computers

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Cloud Storage

• Cloud storage is an Internet service that provides storage to computer users (may or may not be

free)

Page 368

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Cloud Storage

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Cloud Storage

• Users subscribe to cloud storage for a variety of reasons:

Page 369

Access files from any computer Store large files instantaneously Allow others to access their files

View time-critical data and images immediately Store offsite backups

Provide data center functions

Click to view Web Link, click Chapter 7, Click Web Link from left navigation, then click Cloud Storage below Chapter 7

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Optical Discs

• An optical disc consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser

• Typically store software, data, digital photos, movies, and music

• Read only vs. rewritable

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Optical Discs

Page 370

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Optical Discs

• Optical discs commonly store items in a single track that spirals from the center of the disc to the edge

• Track is divided into evenly sized sectors

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Optical Discs

• Care of optical discs

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Optical Discs

A CD-ROM can be read from but not written to

• Read from a CD-ROM drive or CD-ROM player

A CD-R is a multisession optical disc on which users can write, but not erase

A CD-RW is an erasable multisession disc

• Must have a CD-RW drive

Pages 372 – 373 34 Figure 7-29

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Optical Discs

Archive disc

• Stores photos from an online photo center

• Resolution usually is 7200 pixels per photo

• Cost is determined by the number of photos being stored

Picture CD

• Single-session CD-ROM that stores digital

versions of film

• Typically uses a 1024 x 1536 resolution

• Many photo centers offer Picture CD

services

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Optical Discs

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Optical Discs

A DVD-ROM is a high-capacity optical disc on which users can read but not write or erase

• Requires a DVD-ROM drive

A Blu-ray Disc-ROM (BD-ROM) has a storage capacity of 100 GB

DVD-RW, DVD+RW, and DVD+RAM are high-capacity rewritable DVD formats

Pages 375 – 376

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Other Types of Storage

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Other Types of Storage

• Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information

• A tape drive reads and writes data and information on a tape (sequential access)

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Other Types of Storage

• A magnetic stripe card contains a magnetic stripe that stores information

• A smart card stores data on a thin

microprocessor

embedded in the card

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Other Types of Storage

• Microfilm and microfiche store microscopic images of documents on a roll or sheet film

Page 378

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Other Types of Storage

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Other Types of Storage

• Enterprise storage stores huge volumes of data and information for large businesses

– Uses special hardware for heavy use, maximum availability, and maximum efficiency

Page 379

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Putting It All Together

Home user

• 500 GB hard disk

• Cloud storage

• Optical disc drive

• Card reader/writer

• USB flash drive

Small Office/Home Office user

• 1 TB hard disk

• Cloud storage

• Optical disc drive

• External hard disk for backup

• USB flash drive

Mobile

• 250 GB hard disk

• Cloud storage

• Optical disc drive

• Card reader/writer

• Portable hard disk for backup

• USB flash drive

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Putting It All Together

Page 380

Power User

• 2.5 TB hard disk

• Cloud storage

• Optical disc drive

• Portable hard disk for backup

• USB flash drive

Enterprise User (desktop computer)

• 1 TB hard disk

• Optical disc drive

• Smart card reader

• Tape drive

• USB flash drive

Enterprise User (server or mainframe)

• Network storage server

• 40 TB hard disk system

• Optical disc server

• Microfilm or microfiche

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