Transcript Chapter 8
Chapter 8 Secondary Storage College of Computer and Information Science Key Words & Terms • • • • • • • • • • • • • • • • access speed: 读写速度 Blu-Ray (BR): 蓝光 capacity: 容量 CD (compact disc): 紧凑格式盘 CD-R (CD-recordable): 可写CD（一次） CD-ROM (compact disc-read only memory): 只读CD CD-ROM jukebox: CD-ROM光盘库 CD-RW (compact disc rewritable): 可擦写CD（多次） cylinder: 柱面 density: 密度 direct access: 直接读写 disk caching: 磁盘高速缓冲 DVD (digital versatile disc or digital video disc): 数字式通用盘 DVD player: DVD播放器 DVD-R or DVD+R (DVD recordable): 一次性刻录格式 DVD-RAM (DVD-random-access memory):可读写DVD College of Computer and Information Science 8-2 Key Words & Terms • • • • • • • • • • • • • • • • • DVD-ROM (digital versatile disc-read only memory): 只读DVD DVD-RW or DVD+RW (DVD rewritable): 可擦写DVD enterprise storage system: 大型存储系统 Erasable optical disk: 可擦写光盘 file compression: 文件压缩 file decompression: 文件解压 file server: 文件服务器 flash memory card: 闪存卡 floppy disk: 软盘 floppy disk cartridge: 大容量软盘 floppy disk drive (FDD): 软盘驱动器 hard disk: 硬盘 hard-disk cartridge: 移动式硬盘 hard-disk pack: 硬盘盘组 HD DVD (high-definition DVD): 高清DVD head crash: 读写头损坏 hi def (high definition): 高清 College of Computer and Information Science 8-3 Key Words & Terms • • • • • • • • • • • • • magnetic tape: 磁带 magnetic tape reel: 磁带卷 magnetic tape streamer: 流式磁带 mass storage: 海量存储 mass storage devices: 海量存储设备 media: 介质 optical disk: 光盘 optical disk drive: 光盘驱动器 organizational Internet storage: 高速网络存储 PC Card hard disk: PC卡式硬盘 pit: 光盘凹陷处 primary storage: 主存 RAID system: 冗余阵列盘系统 College of Computer and Information Science 8-4 Key Words & Terms • redundant arrays of inexpensive disks (RAID): 冗余阵列 盘 • secondary storage: 辅助存储器 • secondary storage device: 辅助存储设备 • sector: 扇区 • sequential access: 顺序读写 • shutter: 磁盘读写口 • software engineer: 软件工程师 • solid-state storage: 固态存储器 • storage devices: 存储设备 • tape cartridge: 磁带盒 • tape library：磁带库 • track: 磁道 • USB drive: USB驱动器 • write-protection notch: 写保护口 College of Computer and Information Science 8-5 Competencies (Page 1 of 2) • Distinguish between primary and secondary storage • Describe the traditional floppy disk and compare it to high capacity floppy disks • Compare internal hard disks, hard-disk cartridges, and hard-disk packs Page 218 College of Computer and Information Science 8-6 Competencies (Page 2 of 2) • Describe ways to improve hard-disk operations, including disk caching, redundant arrays of inexpensive disks, and data compression and decompression • Discuss the different types of optical disks • Describe solid-state storage, Internet drives, and magnetic tape • Discuss mass storage and mass storage devices Page 218 College of Computer and Information Science 8-7 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 than floppy disks. In this chapter, you will learn about the many types of secondary storage devices including their capabilities and limitations. Page 219 College of Computer and Information Science 8-8 Storage • Primary storage • Secondary storage – Volatile storage – Temporary storage – Nonvolatile storage – Permanent storage • Secondary storage characteristics – – – – Page 220 Media Capacity Storage devices Access speed College of Computer and Information Science 8-9 Secondary Storage Devices • Most desktop microcomputer systems have floppy disks, hard disks, and optical disk drives • Are used to save, back up, and transport data files and programs Page 220 College of Computer and Information Science 8-10 Floppy Disks • Portable or removable storage media • Typically used to store and transfer small word processing, spreadsheet, and other types of files • Floppy disk drives (FDD) – Store data and programs – Retrieves data by reading electromagnetic charges – Also called flexible disks and floppies Page 220 College of Computer and Information Science 8-11 Traditional Floppy Disk • Most common type is 2HD “two-sided, highdensity” • Attributes – – – – – Page 221 Shutter Labels Write-protection notch Tracks Sectors College of Computer and Information Science 8-12 High Capacity Floppy Disks • Known as a floppy-disk cartridge • Require special disk drives • Most widely used is the Zip disk – 100 MB, 250 MB or 750 MB capacity – Used to store multimedia, database, large text, and spreadsheet files Page 221 College of Computer and Information Science 8-13 Hard Disks • • • • • Use thicker, metallic platters for storage Faster than a floppy diskette Large capacity Sensitive instruments There are three types of hard disks: – Internal Hard Disk – Hard-disk cartridge – Hard-disk pack • Performance Enhancements Page 221 College of Computer and Information Science 8-14 Materials that Cause a Head Crash • Head crash is a disaster for a hard disk Return Page 222 College of Computer and Information Science 8-15 Internal Hard Disk • Located inside system unit • Designated as the C drive • Advantages over floppies – Capacity – Access speed Return Page 222 College of Computer and Information Science 8-16 Hard-Disk Cartridges • Removable hard disks • Used to complement internal hard disk Hard-disk cartridge • Capacities of 20 to 100 GB • Iomega is one of the most widely used PC Card Hard Disks Return Page 223 College of Computer and Information Science 8-17 Hard-Disk Packs • Removable hard disk • Massive storage capacity • Common in mainframes • Are utilized by banks and credit card companies Return Page 224 College of Computer and Information Science 8-18 Performance Enhancements • Disk caching • Redundant arrays of inexpensive disks (RAID) • File compression and decompression Page 225 College of Computer and Information Science 8-19 Optical Disks • Hold over 50 gigabytes of data • Attributes – Lands – Pits • Three types – Compact Disc (CD) – Digital Versatile Disc (DVD) – Hi-Def Disc Page 226 College of Computer and Information Science 8-20 Compact Disc • • • • Optical format From 650 MB to 1 GB capacity Rotation speeds vary Three basic types – Read only: CD-ROM – Write once: CD-R – Rewriteable: CD-RW Return Page 226 College of Computer and Information Science 8-21 Digital Versatile Disc • Digital Versatile Disc or Digital Video Disc (DVD) • Similar to CDs, but can store more data • Three basic types – Read only: DVD-ROM – Write once: DVD+R; DVD-R – Rewritable: DVD+RW; DVD-RW; DVD-RAM Return Page 226 College of Computer and Information Science 8-22 High-Definition Disc • Next generation of optical disc • Far greater capacity than DVDs • Three basic types – Read only – Write once – Rewriteable • Two competing hi def formats – HD DVD – Blu-Ray Page 227 College of Computer and Information Science 8-23 Other Types of Secondary Storage • Solid-state storage • Internet hard drives • Magnetic tape Page 229 College of Computer and Information Science 8-24 Ipods and Music From The Internet • The Internet can be used as a medium to locate and play music • A user can create compact discs, or transfer music to a portable player • Requirements – Software – Hardware – Internet Page 230 College of Computer and Information Science 8-25 Solid-State Storage • Flash memory cards – Widely used in notebook computers – Used to record MP3 music files • USB drives Flash memory card – Key ring flash memory devices or flash drives – Connects to a USB port Key ring flash memory Return Page 232 College of Computer and Information Science 8-26 Internet Hard Drives • Known as i-drive or online storage • Low cost and can access information from any location using the Internet • Oriented to either businesses or individuals Return Page 232 College of Computer and Information Science 8-27 Magnetic Tape • External storage • Provides sequential access – Information stored in sequence – Slower than disks which provide direct access • Magnetic tape streamers or tape cartridges used by both mainframes and microcomputers Page 232 College of Computer and Information Science 8-28 Mass Storage Devices • Mass storage refers to the tremendous amount of secondary storage required by large organizations • Mass storage devices are specialized highcapacity secondary storage devices • Enterprise storage system promotes efficient and safe use of data across networks within organizations Page 233 College of Computer and Information Science 8-29 Discussion Questions (Page 1 of 2) • Discuss the traditional and high-capacity floppy disks. • What are the three types of hard disks? Describe three ways to improve hard disk performance. • What are the two most common optical disk formats? What is hi def? Describe the basic types for each format. Page 242 College of Computer and Information Science 8-30 Discussion Questions (Page 2 of 2) • Discuss solid-state storage, Internet hard drives, and magnetic tape. What are the advantages and disadvantages of each? • Discuss mass storage, enterprise storage systems, and mass storage devices. Page 242 College of Computer and Information Science 8-31 End of Chapter 8 College of Computer and Information Science 8-32