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Chapter 7

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Chapter 7

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  1. Chapter 7 Storage

  2. Storage • What isstorage? • Holds data, instructions, and information for future use • Storage medium is physical material used for storage • Also called secondary storage • What is a storage device? • It is the computer hardware that records and/or retrieves items to and from storage media. • What is reading? • It is the process of transferring information from a storage medium into memory.

  3. Magnetic Disks • Magnetic Disks:they use magnetic particles to store items such as data, instructions and information on a disk’s surface. • Formatting: it is the process of dividing the disk into tracks and sectors so the operating system can store and locate data and information on the disk. • Track: it is a narrow recording band that forms a full circle on the surface of the disk. • Sectors: the disk storage locations consist of pie-shaped sections which break the tracks into small arcs. A sector stores 512 bytes of data. • Clusters: for reading and writing purposes, sectors are grouped into clusters. It is the smallest unit of disk space that stores data and information. Also called allocation unit.

  4. Trackis narrow recording bandthat forms fullcircle on disk Sectorstores up to512 bytesof data Magnetic Disks • What aretracks andsectors? Formatting prepares disk for use and marks bad sectors as unusable

  5. Magnetic Disks hard disk installedin system unit • What is ahard disk? • Also called the hard disk drive • It is a storage device that contains one or more inflexible circular platters that magnetically store data, instructions and information. • It is inside an airtight, sealed case inside the system unit. • Hard disks record in two patters: • Longitudinal recording • Perpendicular recording

  6. Magnetic Disks • What is ahead crash? • Occurs when read/write head touches platter surface • Spinning creates cushion of air that floats read/write head above platter • Clearance between head and platter is approximately two-millionths of an inch • A smoke particle, dust particle, or human hair could render drive unusable hair read/write head dust smoke clearance platter

  7. Online Storage • What is online storage? • It is a service on the web that provides hard disk storage to computer users for a monthly fee. • Files can be accessed from any computer with Web access • Large files can be downloaded instantaneously • Others can be authorized to access your data

  8. shutter shell liner magneticcoating metal hub flexible thin film Floppy Disks • Floppy disks are also called a diskette. • It is Portable, inexpensive storage medium. • Thin, circular, flexible film enclosed in 3.5” wide plastic shell. • Floppy disk drive is a device that reads from and writes on a floppy disk. • It is also called a secondary storage. • It is assigned to as DRIVE A:/

  9. Optical Discs Push the button toslide out the tray. What areoptical discs? • It is a type of storage media that consists of a Flat, round, portable metal discs made of metal, plastic, and lacquer • Can be read only or read/write • Most PCs include an optical disc drive Insert the disc,label side up. Push the same buttonto close the tray.

  10. Optical Discs • How is data stored on an optical disc? • Typically stored in single track • Track divided into evenly sized sectors that store items single trackspirals to edgeof disc disc sectors

  11. Types of Optical Discs • CD-ROM • CD-R • CD-RW • DVD-ROM • DVD-R • DVD+R • DVD-RW • DVD+RW • DVD+RAM

  12. Optical Discs • What is aCD-ROM? • Compact disc read-only memory • It is a type of optical disc that users can read but not write or erase. • Typically holds 650 MB to 1 GB • Commonly used to distribute multimedia and complex software

  13. Stores digital versions of roll of film Film developers offer Picture CD service Can be modified using photo editing software Optical Discs • What is aPicture CD?

  14. Optical Discs Must haveCD recorderor CD-R drive • What areCD-Rs and CD-RWs? CD-R (compact disc-recordable) —cdisc you can write on once Cannot erasedisc’s contents CD-RW (compact disc-rewritable) —ceerasable disc you can write onmultiple times Must haveCD-RW softwareand CD-RW drive

  15. Optical Discs What is aDVD-ROM (digital versatile disc-ROM or digital video disc-ROM)? • Must have DVD-ROM drive or DVD player to read DVD-ROM • Stores databases, music, complex software, and movies • Blu-ray discs have storage capacity of up to 27 GB • HD-DVD discs have storage capacity of up to 45 GB • UMD can store up to 1.8 GB

  16. PC Cards • What is aPC Card? • Credit-card-sized device commonlyused in notebook computers • Adds capabilities to computer

  17. Miniature Mobile Storage Media • It allows mobile users easily to transport digital images, music, or documents to and from computers and other devices. • Storage for small mobile devices

  18. Miniature Mobile Storage Media • What is aUSB Flash Drive? • Also called as a pen device • Plugs in a USB port on a computer or mobile device • It is convenient for mobile users because they are small and lightweight enough to be transported on a key chain or in a pocket. • Storage capacities up to 4 GB • May eventually make the floppy disk obsolete

  19. Miniature Mobile Storage Media • What is asmart card? • It is similar in size to a credit card. • Stores data on microprocessor embedded in small card • It contains: • Processor • Input, • Process, • Output, and • Storage capabilities