b_book1.gif (162 bytes)Secondary storage | Multimedia
Use | Features | Types
b_html1.gif (183 bytes)DVD | CD-Recordable Formats| Care & handling | Publishing | Timeline | Examples

b_htmlg.gif (190 bytes)Using HP Surestore |
CD Labels

CD-ROM

  • Makes use of the accuracy of a low powered Laser beam and uses lenses, prisms and mirrors to read data
    (as compared with magnetism for Standard Hard Disks).
  • Typical capacity(1998): 640MB
  • Compact disk (CD) technology
    • CD-ROM ( Compact Disk Read Only Memory).
    • CD-R: (Compact Disk recordable)
    • CD-RW: (Compact Disk rewritable)
    • PhotoCD
    • WORM (Write Once Read Many)
  • Magneto-optical (MO) technology

Use

  • Can hold vast amounts of readily searched text
  • Useful for computer software distribution
    • Windows 95, 98
    • Visual Basic, Delphi
  • Can be creative, entertaining and educational
    • Entertainment (Living books, Need for Speed, Myst),
    • Education (Microsoft Encarta, Musical instruments)
    • Information (Microsoft Encarta (Encyclopedia), MS Technical reference).
For writable CD-ROMS (CD-Recordable)
  • Share Electronic Files
    • Sales tools, catalogs
    • Home multimedia scrapbook
    • Multimedia resume
  • Transport Large Files
    • Multimedia presentations
    • Pre-release software code
    • Graphic files
  • Archive Data Permanently
    • Taxes
    • Blueprints
    • Legal documents

Features

hwsscdp1.gif (15989 bytes)

  • Instead of magnetising iron oxide particles a high power laser beam burns away a small pit for writing and a low power laser beam is reflected off the disk for reading.
  • Can be shared across a network

Technical features

  • 24x CD-ROM (Nov 1997)
    Access Time [85-130msec]
    Buffer size [128-512K]
    Transfer rate MB/sec [approx. 3.6]
    Burst Rate MB/sec [mostly 16.7]
    RPM [approx 6K]
    Mean time between failures(MTBF)  in Power on hours (POH) [60K -125K]
    b_www.gif (422 bytes)(Nov 97) Proh Personal Computers

Types

[CD-Rom]

  • CD-ROM ( Compact Disk Read Only Memory).
    Data imprinted by the manufacturer, 540 to 738MB storage
  • PhotoCD
    Developed by Kodak for storing digitised photos.
  • CD-R: (Compact Disk recordable)
    • A plastic disk with a metal film, may be written to once by the user. Up to 650 MB
    • Can have many format (see table below).
      Multi-session allows the CD to written to many times.
      (Most CD-ROM drives in PC's are still single session).
    • or WORM (Write Once Read Many)
      An early form of optical technology. A metal film disk, may be written to once by the user. 122 to 640Mb storage. Still used by banks to make a permenant backup of data.
  • CD-RW : (Compact Disk rewritable)
    • Data may be written and erased.
    • (1998) Speed 2x write 6x read. Unfortunately not compatible with most CD-ROM drives in use today
      (Cost: HP CD-Writer Plus 7200i approx NZ$900)
      (Saarinen,J. & Sengstack, J., 1998 Jul)
    • (1997) Early CD-RW drive in the NEXT computer. Stores 281 to 3200MB data

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[Rev: 08/11/98] 27-July-97 © 1997-98 V/2-Com (Verhaart), P O Box 8415, Havelock North, New Zealand.