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Chapter 08: Secondary StorageChapter 08: Secondary StorageChapter 08: Secondary StorageChapter 08: Secondary Storage
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CompetenciesCompetencies (Page 1 of 2)(Page 1 of 2)
⢠Distinguish betweenDistinguish between primaryprimary andand secondary storagesecondary storage
⢠Discuss the important characteristics of secondaryDiscuss the important characteristics of secondary
storage, including media, capacity, storage devices, andstorage, including media, capacity, storage devices, and
access speedaccess speed
⢠DescribeDescribe hard disk plattershard disk platters,, trackstracks,, sectorssectors, and, and headhead
crashescrashes
⢠CompareCompare internalinternal andand external hard drivesexternal hard drives
⢠Discuss performance enhancements includingDiscuss performance enhancements including
disk cachingdisk caching,, RAIDsRAIDs,, file compressionfile compression, and, and
file decompressionfile decompression
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CompetenciesCompetencies (Page 2 of 2)(Page 2 of 2)
⢠Define optical storage includingDefine optical storage including compactcompact,, digital versatiledigital versatile,,
andand high-definition discshigh-definition discs
⢠Define solid-state storage, includingDefine solid-state storage, including solid-state drivessolid-state drives,,
flash memoryflash memory, and, and USB drivesUSB drives
⢠DefineDefine cloud storagecloud storage andand cloud storage servicescloud storage services
⢠Discuss mass storage devices, enterprise storage systems,Discuss mass storage devices, enterprise storage systems,
andand storage area networksstorage area networks
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IntroductionIntroduction
⢠Data storage has expanded from text and numericData storage has expanded from text and numeric
files to include digital music files, photographicfiles to include digital music files, photographic
files, video files, and much more.files, video files, and much more.
⢠These new types of files require secondary storageThese new types of files require secondary storage
devices with much greater capacity.devices with much greater capacity.
⢠In this chapter, you learn aboutIn this chapter, you learn about
the many types of secondarythe many types of secondary
storage devices including theirstorage devices including their
capabilities and limitations.capabilities and limitations.
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Secondary Storage DevicesSecondary Storage Devices
⢠Provides permanent or nonvolatileProvides permanent or nonvolatile
storagestorage
⢠Data and programs can be retainedData and programs can be retained
after the computer has been shut offafter the computer has been shut off
⢠Most desktop microcomputer systemsMost desktop microcomputer systems
have both hard and optical disk driveshave both hard and optical disk drives
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Hard DisksHard Disks
⢠Use rigid, metallic platters for storageUse rigid, metallic platters for storage
⢠Files organized usingFiles organized using trackstracks,, sectorssectors, and, and cylinderscylinders
⢠Large capacity (terabytes)Large capacity (terabytes)
⢠Sensitive instrumentsSensitive instruments
⢠Two types of hard disks:Two types of hard disks:
â Internal Hard DiskInternal Hard Disk
â External Hard DisksExternal Hard Disks
⢠Performance enhancementsPerformance enhancements
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Materials that Cause a Head CrashMaterials that Cause a Head Crash
⢠AA head crashhead crash is a disaster for a hard disk,is a disaster for a hard disk,
not to mention the data stored on the disknot to mention the data stored on the disk
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Internal Hard DiskInternal Hard Disk
⢠Located inside system unit and oftenLocated inside system unit and often
designated as the C: drivedesignated as the C: drive
⢠Used to store programs and data filesUsed to store programs and data files
⢠Advantages over removable mediaAdvantages over removable media
â CapacityCapacity
â Access speedAccess speed
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External Hard DisksExternal Hard Disks
⢠Removable hard disksRemovable hard disks
⢠Used to complement internal hard disk with anUsed to complement internal hard disk with an
unlimited amount of additional storageunlimited amount of additional storage
⢠Capacities extend into the terabytes (TBs)Capacities extend into the terabytes (TBs)
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Performance EnhancementsPerformance Enhancements
⢠Disk cachingDisk caching to improveto improve
hard disk performancehard disk performance
⢠Redundant arrays ofRedundant arrays of
inexpensive disks (RAID)inexpensive disks (RAID)
to expand storage andto expand storage and
to improve access speedto improve access speed
⢠File compressionFile compression
andand decompressiondecompression
to increase capacityto increase capacity
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Optical DisksOptical Disks
⢠Hold over 100 gigabytes (GB) of dataHold over 100 gigabytes (GB) of data
⢠AttributesAttributes
â LandsLands
â PitsPits
⢠Three typesThree types
â Compact Disc (CD)Compact Disc (CD)
â Digital Versatile Disc (DVD)Digital Versatile Disc (DVD)
â Blu-Ray (Hi-Def) DiscBlu-Ray (Hi-Def) Disc
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Compact Disc (CDs)Compact Disc (CDs)
⢠Optical formatOptical format
⢠Capacity of 650 MB to 1 GBCapacity of 650 MB to 1 GB
⢠Rotation speeds varyRotation speeds vary
⢠Three basic typesThree basic types
â Read only (Read only (CD-ROMCD-ROM))
â Write once (Write once (CD-RCD-R))
â Rewriteable (Rewriteable (CD-RWCD-RW))
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Digital Versatile Discs (DVDs)Digital Versatile Discs (DVDs)
⢠Like CDs, but newer format calledLike CDs, but newer format called digitaldigital
versatile discversatile disc oror digital video disc (DVD)digital video disc (DVD)
⢠Capacity of 4.7 GB to 17 GBCapacity of 4.7 GB to 17 GB
⢠Three basic typesThree basic types
â Read onlyRead only
((DVD-ROMDVD-ROM))
â Write onceWrite once
((DVD+RDVD+R andand DVD-RDVD-R))
â RewriteableRewriteable
((DVD+RWDVD+RW,, DVD-RWDVD-RW, and, and DVD-RAMDVD-RAM))
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Blu-ray Disc (BDs)Blu-ray Disc (BDs)
⢠Next generationNext generation optical discoptical disc for recordingfor recording
high-definition (hi def) videohigh-definition (hi def) video
⢠Capacity of 25 GB to 100 GBCapacity of 25 GB to 100 GB
⢠Blu-ray optical drives are usually capable ofBlu-ray optical drives are usually capable of
reading standard DVDs and CDs in additionreading standard DVDs and CDs in addition
to Blu-ray discsto Blu-ray discs
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Solid-State StorageSolid-State Storage
⢠Solidâstate drives (SSDs)Solidâstate drives (SSDs)
â Faster and more durableFaster and more durable
⢠Flash memory cardsFlash memory cards
â Widely used in computers, cameras,Widely used in computers, cameras,
and portable devices such as mobileand portable devices such as mobile
phonesphones
⢠USB DrivesUSB Drives (or(or Flash DrivesFlash Drives))
â Compact and easily transportedCompact and easily transported
â Capacity of 1 GB to 256 GBCapacity of 1 GB to 256 GB
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Making IT Work for YouMaking IT Work for You
Flash Camcorders, YouTube, and MySpaceFlash Camcorders, YouTube, and MySpace
⢠Flash-based camcorders have made creatingFlash-based camcorders have made creating
digital video simpler and more affordabledigital video simpler and more affordable
⢠Easily upload your creations to photo- andEasily upload your creations to photo- and
video-sharing Web sites on the Internetvideo-sharing Web sites on the Internet
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Cloud StorageCloud Storage
⢠Cloud computingCloud computing is where the Internetis where the Internet
acts as a âcloudâ of serversacts as a âcloudâ of servers
â Applications provided as aApplications provided as a serviceservice rather than arather than a productproduct
(for example,(for example, cloudcloud oror online storageonline storage))
⢠Cloud storage servicesCloud storage services
make it easy tomake it easy to
upload and shareupload and share
files with anyonefiles with anyone
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Mass Storage DevicesMass Storage Devices
⢠Organizations require tremendous amounts ofOrganizations require tremendous amounts of
secondary storage calledsecondary storage called mass storagemass storage
⢠Enterprise storage systems ensure data securityEnterprise storage systems ensure data security
using specialized strategies and devices, such asusing specialized strategies and devices, such as
â File serversFile servers
â Networked attached storage (NAS)Networked attached storage (NAS)
â RAID systemsRAID systems
â Tape librariesTape libraries
â Organizational cloud storageOrganizational cloud storage
â Storage Area Network (SAN)Storage Area Network (SAN)
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Enterprise Storage SystemsEnterprise Storage Systems
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Careers In ITCareers In IT
⢠Software engineersSoftware engineers analyze usersâ needs andanalyze usersâ needs and
create application softwarecreate application software
⢠General employer requirementsGeneral employer requirements
â Bachelors degree inBachelors degree in
computer sciencecomputer science
â Extensive knowledge ofExtensive knowledge of
computers and technologycomputers and technology
â Communication and analytical skillsCommunication and analytical skills
⢠Annual salary of $63,000 to $98,500Annual salary of $63,000 to $98,500
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A Look to the FutureA Look to the Future
Your Entire Life Recorded on a Single DiskYour Entire Life Recorded on a Single Disk
⢠Future secondary storage disks willFuture secondary storage disks will
eventually store terabytes (TB) oreventually store terabytes (TB) or
petabytes (PB)petabytes (PB)
â Your entire life captured inYour entire life captured in
digital video on a single discdigital video on a single disc
â Currently developing programsCurrently developing programs
that can scan photos and videosthat can scan photos and videos
for a particular personâs facefor a particular personâs face
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Open-Ended Questions(Page 1 of 2)Open-Ended Questions(Page 1 of 2)
⢠What are the two types of hard disks? DescribeWhat are the two types of hard disks? Describe
three ways to improve hard disk performance.three ways to improve hard disk performance.
⢠Compare solid-state and hard disk storage.Compare solid-state and hard disk storage.
⢠List and compare the three most common opticalList and compare the three most common optical
disc formats?disc formats?
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Open-Ended Questions (Page 2 of 2)Open-Ended Questions (Page 2 of 2)
⢠Describe cloud computing and cloud storage.Describe cloud computing and cloud storage.
⢠Discuss mass storage systems including enterpriseDiscuss mass storage systems including enterprise
storage systems and storage area networks.storage systems and storage area networks.
Hinweis der Redaktion
Secondary storage permanently saves information for future use; to share information with others; to modify at later date Secondary storage is nonvolatile â stores programs and data as opposed to temporary storage (RAM) Characteristics include: Media or medium â actual physical materials that holds the data and programs Capacity â measures how much a particular storage medium can hold Storage devices â hardware that reads data and programs from storage media (most also write to storage media) Access speed or access time â measures the amount of time required by the storage device to retrieve data and programs Writingâ process of saving information to the secondary storage device Reading â process of accessing information from secondary storage
Optical disks â large storage capacity (Key Term) Hard disk â large storage capacity and fast retrieval times
Composed of metallic rather than plastic disks Platters â rigid metallic, stacked one on top of another A cylinder (Key Term) runs through each track of a stack of platters Fast information storage and retrieval Read-write head is .000001 inch above surface
Head crashes occur when the read-write head contacts with the disk surface or with particles on the disk's surface Head crashes are now rare A smoke particle, human hair, or fingerprint could cause a head crash
Located inside the system unit Used for storing the operating system, other programs, and large data files You should perform routine maintenance and periodically backup all important files
Capacity limited only by number of removable devices you want to add to your system; used to complement internal hard disk. Includes USB, FireWire, eSATA external disk enclosures PC Card hard disk (Key Term) available for notebooks with a capacity of up to 5 GB
Disk caching Uses hardware and software to anticipate data needs; performs function similar to RAM caching; improves processing by acting as a temporary high-speed holding area between a secondary storage device (Key Term) and the CPU Frequently used data is stored in memory; when needed, the access time is much faster Redundant arrays of inexpensive disks (RAID) Groups of low cost hard-disk drives grouped together using networks and special software Performs as a single large-capacity disk; but faster than a single disk of comparable size Often used by Internet servers and large organizations File compression and decompression Increase storage capacity Reduce space required for storage; reduce up to Âź of original size WinZip and UltimateZip are well-known programs, and you can also use utility programs in Windows XP
Use laser technology. CD (Key Term) and DVD (Key Term) are optical disk formats. Compact, high capacity form of permanent storage (up to 50 gigabytes of data) Optical discs are read by an optical disc drive Laser beam writes by creating a pattern of pits (holes) and lands (flat areas) to encode data bits Laser beams reflect off the pits and lands to read the data Rotational speed determines how fast data can be transferred from the CD Optical disks come in many different sizes Most common is 4 ž inches Stored in a protective case called jewel boxes
CD stands for compact disc Standard on most computers; can store from 650 MB up to 1 GB Speed determines how fast data can be transferred Read only: CD-ROM Commercial music CD Read only means it cannot be written on or erased Used to distribute large databases and references Write once: CD-R (CD-recordable) Used to archive data or to record music downloaded from the Internet Rewriteable: CD-RW Known as erasable optical disks (Key Term) Can be changed Used to create and edit multimedia presentations Ideal for use as permanent data archives for essential company information
Blu-ray, also known as BDs Have a capacity of 25 to 100 gigabytes Blu-ray has seemingly won the battle as the standard high definition video disc
Solid state drives are faster and more durable (no moving parts) than hard drives Require less power Contain solid state memory instead of magnetic disk to store data Flash memory cards are one type of solid state device.
Mass storage devices that support enterprise storage systems are File servers (Key Term) â dedicated computer with very large storage capacities that provide user access to fast storage and retrieval of data RAID systems (Key Term) â larger versions of the specialized devices discussed earlier in this chapter that enhance organizational security by constantly making backup copies of files moving across the organizationâs networks Tape library (Key Term) â device that provides automatic access to data archived on a large collection or library of tapes DVD-ROM and CD-ROM jukeboxes (Key Term) â provide automatic access to a large collection or library of optical disks Organizational Internet Storage (Key Term) â high-speed Internet connection to a dedicated remote organizational Internet drive site
Are there downsides? Could your personal video log be used to incriminate you in a court of law? Could someone elseâs video log be an invasion of your right to privacy?
Have students turn to the end of Chapter 8 in their textbooks to view the same âOpen-Endedâ questions/statements
Have students turn to the end of Chapter 8 in their textbooks to view the same âOpen-Endedâ questions/statements