This distinguishing indication of the DVD denotes more storage capacity. Enhanced storage is a prominent feature that gives a DVD supreme advantage over a CD.

Storage Capacity

A DVD stores 12 times the information stored on a CD ROM. A CD holds up to 700 MB of information whereas a DVD can hold 4.7 GB of information on a single layer and 8.4GB on a dual layer. (DVDs are usually single layered. But, a DVD-R DL is dual layered.) And, a double sided dual layered DVD stores 17 GB of information that is equivalent to data stored on 26 CD ROMs.

CDs have led to the evolution of DVDs over a period of 25 years. But, a DVD has tremendous data storage capacity, much more than a CD.

Quite a few reasons can be attributed to this maximisation of storage capacity.

• In a CD, data is stored on a single side whereas a DVD holds information on both the sides.


• Both the CDs and the DVDs store information in non reflective holes called pits and flat areas called lands as ones and zeros in binary codes. The pits have lower width in DVDs and are packed between narrower lands compared to a CD.


• The track distance (the space between the rings on pits) is 0.74 micron in a DVD, compared to 1.6micron in a CD. This enables storage of more information.


• Further, the redundant information in the pitch of the DVD is limited to 750 nanometres compared to 1600 nm in a CD.
  
  Information on the DVD is not only quantitatively but also qualitatively better than the one stored on a CD.
  
  Accurate Reading
  
  A CD player uses a laser wave length of 780-790 nm to read the digital pits in a CD ROM whereas the laser wave length used on a DVD is 635-650 nm. Shorter laser wave length leads to accurate reading of the densely packed information.
  
  However, DVDs do not score over CDs in just the qualitative betterment of the information. They also enjoy better data transfer rates.
  
  Data Transfer
  
  A DVD drive offers the facility of transferring data at the rate of 1,108 kb/s.
  
  DVDs like the CDs are easily portable. This is an advantage when viewed in the light of the fact that if 17 GB of information were to be sent, it would require 11,000 floppy disks. Compare transporting so many disks to sending a single DVD.
  
  Life span
  
  DVDs last longer than CDs, for they do not degrade with each usage.
  
  When DVDs arrived on the data storage scene they replaced the floppy drives almost instantly. Though, the 10 inch floppy disk had made much technological progress and had sized down to 3.5 inches, its data storing capacity remained woefully low. Thus DVDs enjoyed a justified popularity. Users often wonder if CDs might go the floppy way. DVDs are better than CDs and would undoubtedly replace them but, they too, have a few inherent drawbacks.
  
  Disadvantages Inherent in DVDs
  
  
  • DVDs presumably enjoy longer life spans but, there are quite a few instances when the data stored on them turns inaccessible. For, as mentioned, DVD stores data in layers. When a novice or ignorant user bends them while pulling it out of the case, the bend separates the layers.
  
  
  • The player cannot read the data on the DVD if the protective film covering the DVD either bubbles up or peels away. This could either be pointed to a manufacturing defect or storage of the media in a hot humid place.
  
  
  • Improper handling of the device also leaves its own damaging impact. Data that lies on the scratched surface of a DVD cannot be accessed.
  
  
  These are the few limitations of a DVD. The limitations far outweigh the plenty of advantages on offer. However, the choice of an apt data storage media is also determined by the price factor.
  
  The Cost Difference
  
  A blank DVD costs 4 to 10 times more than an audio CD. But, cost should never be a major deterrent for; a DVD holds much more information than a CD thus reducing the cost per bit of information stored.
  
  DVDs are here to stay. The increased data storing capacity, speed of transferring data and easy retrieval of it, has made it prominently popular.

  Article Source: http://www.my-article-dashboard.com

  James Walsh is a freelance writer and copy editor. If you are concerned about data loss and would like more information on Data Recovery see www.fields-data-recovery.co.uk

  Please Rate this Article

  5 out of 54 out of 53 out of 52 out of 51 out of 5 

  Not yet Rated

  
  Additional Articles From - Home | Computers | Data Recovery
  • The Overall Procedure for ADSENSE! - By : Adnann Ahmedd
    
  • Repairing Outlook Express Mail Database - By : Eugine Kharinskiy
    
  • Recovering Digital Pictures from Hard Disks and Flash Memory Cards - By : Stas Ermolov
    
  • Disaster and Data Recovery Planning - By : bozenaj
    
  • Un-Scientific Approach to NTFS Recovery - By : Data Recovery
    
  • Hard Disk Recovery Made Easy - By : Nik Kaufman
    
  • RegistryEasy - advanced PC maintenance tool - By :
    
  • COMPUTER BACKUPS - By : Sudhir.K.Sharma
    
  • To Know Your File Formats- most suitable file format - By : Maya Sharma
    
  • OST to PST convertor - By : Recovery Toolbox Inc