Author: Roy Eassa
Date: 09:05:06 09/06/02
Go up one level in this thread
On September 06, 2002 at 10:58:55, William H Rogers wrote: >On September 06, 2002 at 10:17:06, Roy Eassa wrote: > >>On September 05, 2002 at 17:49:35, William H Rogers wrote: >> >>>Sarah that sounds like my sons excuse to his teachers "my dog ate my homework" >>>VCR tapes and floppy disks are suppost to have a useful life of about 10 years, >>>while CD's and DVD's should last about 100 years. Scratched CD's can easily be >>>repaired. The surface of the CD is only a plastic coating to protect the metal >>>disk that contains the information. >>>Just joking about the 'dog' >>>Bill >> >> >>Aren't the pits (the data) actually in plastic, with the metal there for >>reflective purposes only? >No. My engineers have told me that the metal is where the data is recoreded, and >that is why you can polish the surface of a damaged cd and restore its contents. >I am talking about scratches, etc. By encasing the metal in plastic, the metal >is kept from oxidizing and thus extending its life for years and years. >Bill Still, respectfully, I've definitely read detailed articles that show that the pits are burned into the part of the plastic that's right next to the metal (and far from the scratchable surface). Further, I've read that it's a common misconception that the data is in the metal. I'll do a search on the 'net to see if I can back this up. Here's one to start: http://www.ee.washington.edu/conselec/CE/kuhn/cdaudio/95x6.htm "Pits are formed in the polycarbonate disk by an injection molding process."
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.