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Learn about primary vs. secondary storage, characteristics of secondary storage devices, hard disk structures, internal vs. external hard drives, performance enhancements like disk caching and file compression, optical and solid-state storage, cloud storage, mass storage devices like enterprise systems and storage area networks.
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Competencies(Page 1 of 2) • Distinguish between primary and secondary storage • Discuss the important characteristics of secondary storage, including media, capacity, storage devices, and access speed • Describe hard disk platters, tracks, sectors, and head crashes • Compare internalandexternal hard drives • Discuss performance enhancements includingdisk caching, RAIDs, file compression, andfile decompression
Competencies (Page 2 of 2) • Define optical storage including compact, digital versatile, and high-definition discs • Define solid-state storage, including solid-state drives, flash memory, and USB drives • Define cloud storage and cloud storage services • Discuss mass storage devices, enterprise storage systems, and storage area networks
Introduction • Data storage has expanded from text and numeric files to include digital music files, photographic files, video files, and much more. • These new types of files require secondary storage devices with much greater capacity. • In this chapter, you learn aboutthe many types of secondarystorage devices including theircapabilities and limitations.
Storage • Primary storage • Volatile storage • Temporary storage • Random Access Memory (RAM) • Secondary storage • Nonvolatile storage • Permanent storage • Secondary storage characteristics • Media • Capacity • Storage devices • Access speed
Secondary Storage Devices • Provides permanent or nonvolatile storage • Data and programs can be retained after the computer has been shut off • Most desktop microcomputer systems have both hard and optical disk drives
Hard Disks • Use rigid, metallic platters for storage • Files organized using tracks, sectors, and cylinders • Large capacity (terabytes) • Sensitive instruments • Two types of hard disks: • Internal Hard Disk • External Hard Disks • Performance enhancements
Materials that Cause a Head Crash • A head crash is a disaster for a hard disk, not to mention the data stored on the disk Return
Internal Hard Disk • Located inside system unit and often designated as the C: drive • Used to store programs and data files • Advantages over removable media • Capacity • Access speed Return
External Hard Disks • Removable hard disks • Used to complement internal hard disk with an unlimited amount of additional storage • Capacities extend into the terabytes (TBs) Return
Performance Enhancements • Disk caching to improvehard disk performance • Redundant arrays of inexpensive disks (RAID)to expand storage andto improve access speed • File compression and decompressionto increase capacity Return
Optical Disks • Hold over 100 gigabytes (GB) of data • Attributes • Lands • Pits • Three types • Compact Disc (CD) • Digital Versatile Disc (DVD) • Blu-Ray (Hi-Def) Disc
Compact Disc (CDs) • Optical format • Capacity of 650 MB to 1 GB • Rotation speeds vary • Three basic types • Read only (CD-ROM) • Write once (CD-R) • Rewriteable (CD-RW) Return
Digital Versatile Discs (DVDs) • Like CDs, but newer format called digital versatile disc or digital video disc (DVD) • Capacity of 4.7 GB to 17 GB • Three basic types • Read only(DVD-ROM) • Write once(DVD+R and DVD-R) • Rewriteable(DVD+RW, DVD-RW, and DVD-RAM) Return
Blu-ray Disc (BDs) • Next generation optical disc for recording high-definition (hi def) video • Capacity of 25 GB to 100 GB • Blu-ray optical drives are usually capable of reading standard DVDs and CDs in addition to Blu-ray discs Return
Solid-State Storage • Solid–state drives (SSDs) • Faster and more durable • Flash memory cards • Widely used in computers, cameras, and portable devices such as mobile phones • USB Drives (or Flash Drives) • Compact and easily transported • Capacity of 1 GB to 256 GB
Making IT Work for YouFlash Camcorders, YouTube, and MySpace • Flash-based camcorders have made creating digital video simpler and more affordable • Easily upload your creations to photo- andvideo-sharing Web sites on the Internet
Cloud Storage • Cloud computing is where the Internetacts as a “cloud” of servers • Applications provided as a service rather than a product (for example, cloud or online storage) • Cloud storage servicesmake it easy toupload and sharefiles with anyone
Mass Storage Devices • Organizations require tremendous amounts of secondary storage called mass storage • Enterprise storage systems ensure data security using specialized strategies and devices, such as • File servers • Networked attached storage (NAS) • RAID systems • Tape libraries • Organizational cloud storage • Storage Area Network (SAN)
Careers In IT • Software engineers analyze users’ needs and create application software • General employer requirements • Bachelors degree incomputer science • Extensive knowledge ofcomputers and technology • Communication and analytical skills • Annual salary of $63,000 to $98,500
A Look to the FutureYour Entire Life Recorded on a Single Disk • Future secondary storage disks will eventually store terabytes (TB) or petabytes (PB) • Your entire life captured indigital video on a single disc • Currently developing programsthat can scan photos and videosfor a particular person’s face
Open-Ended Questions(Page 1 of 2) • What are the two types of hard disks? Describe three ways to improve hard disk performance. • Compare solid-state and hard disk storage. • List and compare the three most common optical disc formats?
Open-Ended Questions (Page 2 of 2) • Describe cloud computing and cloud storage. • Discuss mass storage systems including enterprise storage systems and storage area networks.
