Re: Do CD's Degrade?, and DCC Question

[mujad@uxa.ecn.bgu.edu (James A. Drenter)]

In simple terms, yes it is currently believed that CDs begin to oxidize
after as few as 10 years.  The recording surface of a CD is made
primarily of aluminum, which (like all metals) oxidizes when exposed to
the air.  You may be wondering "Well aren't these things encased in
plastic to prevent that?"  Yes and no.  The plastic CDs are encased in
is to protect them from you, not the air.  Therefore, to save money,
most CD manufacturers use as little coating as possible.  Don't worry
too much though, I imagine the average CD will easily out live you, and
they will definately out live a magnetic tape.  10 years is more the
exception (I would put it closer to 40-50).
You see, what happens is as the thin aluminum layer oxidizes, the
polished surface loses its reflective properties, and the laser used to
read the music suddenly stops reflecting off the disk.  Thereby, the
disk becomes useless.

Incidentally, don't expect those new DAT decks to play your current
standard cassettes, they won't.  The DAT standard is a completely
different type of tape (physically, as well as operationally).  It is
thicker, and resembles more of a small video tape (such as VHS-C).  DO
NOT BUY A DAT SYSTEM IF YOU'RE NOT GOING TO USE DATs EXCLUSIVELY.

Hope I could help.

-- 
.........................................................................
 James Drenter           \\      Everywhere is walking distance         \\
  mujad@uxa.ecn.bgu.edu   \\       If you have the time.                 \\
   mujad@ecnuxa.bitnet     \\                      --- Steven Wright      \\