STORAGE devices by pengxiang

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									STORAGE devices & media

       GCSE Information
 STORAGE
 devices
• FLOPPY DISKS
• 1.44Mb (megabytes) storage
  capacity is quite limiting by
  today’s standards: how much space is needed for a 2 page
  Publisher piece which has a few basic bits of clip art included?
• Portable
• Can carry work easily from machine to machine (including
  carrying a virus….)
• Easily damaged: store them on a speaker or on top of the monitor
  & contents will be erased
• Water/food & floppy don’t mix….
STORAGE devices
• Hard Disks
10Gb (gigabyte) is normal
20Gb or higher available
Non-volatile (i.e. when power
Removed, contents are retained)




                                  Technical info on the web: click here
STORAGE devices
• CDROMs …CD-R … CD-RW… There are now countless games, software
  applications, encyclopaedias, presentations and other multimedia programs
  available on CD-ROM and what was originally designed to carry 74 minutes of
  high-quality digital audio can now hold up to 650MB of computer data, 100
  publishable photographic scans, or even 74 minutes of VHS-quality full-motion
  video and audio. Many discs offer a combination of all three, along with other
  information besides.
• Today’s mass produced CD-ROM drives are faster and cheaper than they’ve
  ever been. Consequently, not only is a vast range of software now routinely
  delivered on CD-ROM, but many programs (databases, multimedia titles,
  games and movies, for example) are also run directly from CD-ROM - often
  over a network.
• They are quite robust – especially in comparison with floppy disks.
• They are portable & now cheap (10 blank CDs cost around £5)
• Useful for carrying around important data/work
• Now CD WRITERS are cheaper, this becomes a cheap and economical way to
  store your work …. BACKUP YOUR WORK or risk TREMENDOUS
  LOSSES (time and money)
                                              Details on the web: click here
STORAGE devices
• DVD
• DVD-5 is a single-sided single-layered disc boosting capacity seven-fold to
  4.7GB
• DVD-9 is a single-sided double-layered disc offering 8.5GB
• DVD-10 will be a 9.4GB dual-sided single-layered disc
• DVD-18 will increase capacity to a huge 17GB on a dual-sided dual-layered
  disc.




                                         Details on the web: click here
STORAGE devices
• TAPES and tape drives
• Used for backing up
• Capacities vary between 1Gb and 100Gb
• There are different types of tape & drive: QIC, TRAVAN, DAT, DLT
• Tape capacities quoted are compressed capacities: One function of backing up is
  to compress (shrink by mathematically calculating alternative ways of storing
  the data). In theory, the compression ration is 2:1. A 5Gb (native) tape then has a
  theoretical 10Gb capacity. In reality, the compression ration achieved is closer to
  1.6:1.
• Easy to handle, portable, vast capacities
• Slow



                             Details on the web: click here
                             And for BACKUP information: click here
STORAGE devices
• ZIP drives and others
  Read the magazines and you will soon find alternative ways to save (store) your
  work.
• IOMEGA ZIP drives use disks that are similar to a floppy disk but store up to
  100Mb or 250Mb of data. They are good for saving work and carrying it with
  you from machine to machine. Clearly, a ZIP drive would be needed on each
  machine visited.
• The ZIP drives are portable with USB versions for hot plug & play providing the
  operating system (e.g. Windows) supports USB devices.
• ZIP drives are not too expensive either…




                                 Details on the web: click here
STORAGE devices

You need to be able to:
• Discuss different devices and what they can be
  used for
• Be aware of capacities and limitations
• Be aware of costs
• Know advantages and disadvantages for each

								
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