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Storing Data: Electronic Filing Cabinets

Storing Data: Electronic Filing Cabinets. What You Will Learn. Difference between memory and storage How storage media are categorized Measuring a storage device’s performance How data is stored on hard and floppy disks Characteristics of hard drives Uses of removable disks

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Storing Data: Electronic Filing Cabinets

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  1. Storing Data: Electronic Filing Cabinets What You Will Learn • Difference between memory and storage • How storage media are categorized • Measuring a storage device’s performance • How data is stored on hard and floppy disks • Characteristics of hard drives • Uses of removable disks • Various optical storage media • New storage media

  2. What is the difference between memory and storage? • Storage devices hold programs and data in units called files • Files are stored in directories or folders • Memory is a temporary workplace where the computer transfers the contents of a file while it is being used Hard Drive RAM memory

  3. Why is storage necessary? • Storage retains data when the computer is turned off • Storage is cheaper than memory • Storage plays an important role during startup • Storage plays an input role when starting applications • Storage is needed for output • Storage devices can hold a large amount of data

  4. What is a storage device? • Hardware that is capable of retaining data when electricity is turned off • Able to read (retrieve) data from a storage medium (disk/tape) • Able to write (record) data to a storage medium

  5. What are the types of storage technologies? • Sequential- Hardware that reads and writes data in a serial (one after the other) fashion • Random Access- Hardware that reads and writes data without going through a sequence of locations • Magnetic- Hardware that uses disks or tapes that are coated with magnetic material • Optical- Hardware that uses laser beams to read data from plastic disks • Solid State- Devices that use nonvolatile memory chips to read and write data

  6. Sequential – Magnetic Storage Tape Backup Unit Random Access – Magnetic Storage Floppy Drive Hard Drive Jaz Drive Zip Drive

  7. Sequential – Optical Storage CD ROM / DVD Drive Magnetic – Optical Storage Magneto-Optic (MO) Drive

  8. Solid State Storage Memory Stick Smart Card Compact Flash Memory Flash Memory PC Card Micro Drive

  9. How is a storage device’s performance measured? • Capacity- The number of bytes of data that a device can hold • Access Time- The amount of time it takes for the device to begin reading data; measured in milliseconds (ms) Hard Drive CD ROM / DVD Floppy Disk Capacity- 720KB to 1.44 MB Access Time-100ms Capacity- Up to 80 GB Access Time-6 to 12ms Capacity-CD Rom 650MB; DVD 17GB Access Time-80 to 800ms

  10. Hard Disk Drives

  11. What are hard disk drives? • A high speed, high capacity storage device • Consists of metal disks called platters • Contains two or more stacked platters with read/write heads for each side • Works similarly to floppy disk drives

  12. What affects a hard disk’s performance? • Seek time or positioning performance- How quickly the read/write head positions itself and begins transferring information. Measured in milliseconds (ms) • Spindle speed or transfer performance- How quickly the drive transfers data. Measured in rotations per minute (RPM)

  13. What are hard disk interfaces? • Enables the hard disk to communicate with the CPU by way of the hard disk controller • Types of interfaces • Integrated Drive Electronics (IDE)- also called ATA or IDE/ATA • Serial ATA interfaces, also known as SATA150 • Small Computer System Interface (SCSI) • FireWire/IEEE 1394

  14. What is a removable hard disk? • Platters are enclosed in a cartridge which can be inserted or removed from a drive • Used for data archiving and data backup • Usually connected via USB Jaz Drive

  15. What is a tape backup unit? • A device used to store large amounts of data that are not used frequently • Uses cassette type reel to reel plastic tape Tape Backup Unit

  16. CD - ROM & DVD

  17. What is a CD-ROM? • Stands for compact disk-read only memory • CD-ROM drives can not write data to disks • Capable of storing 700MB of data • Used for storing operating systems, large application programs, and multimedia programs

  18. How does a CD-ROM drive work? • Laser beams read microscopic patterns of data on the disk’s surface • Disks contain indentations (pits) and flat reflective areas (land) • The computer interprets the pits as 0’s and the lands as 1’s

  19. What is CD-R and CD-RW? CD-R CD-RW • Disks that can be read and written to • Disks are erasable • Disks can be written to many times • Drives that are capable of reading, writing and erasing data • Disks that can be read and written to • Disks can only be written to “once” • Drives that are capable of reading and writing data

  20. What is DVD? • Stands for digital video disk • Uses similar technology as CD-ROM • Capable of storing up to 17GB of data • Data transfer rate comparable to hard disk drive • Compatible with CD-ROM disks • DVD-RAM- Ability to read/write data

  21. Solid State Storage

  22. What is solid state storage? • Nonvolatile memory chips used to retain data • Solid state storage devices do not have moving parts • Solid state storage devices are small, lightweight, reliable, and portable

  23. Types of solid state storage devices • PC or PCMCIA card- Credit card sized device used mainly with notebook computers; Various functions (modem, adapter, memory and storage)

  24. Types of solid state storage devices • Flash memory card- Wafer thin card used with cellular phones, MP3 players, and digital cameras • Types of flash memory cards- SmartMedia card, CompactFlash card, and Sony’s Memory Stick SmartMedia CompactFlash Memory Stick

  25. Types of solid state storage devices • Smart card- Credit card sized device combining flash memory with a microprocessor; Used as a credit card; Has more functionality, convenience, and safety than credit cards

  26. THE END

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