Re: tlug: CD-R reliability

[Scott Stone <sstone@example.com>]

On Mon, 3 Aug 1998, Marcus Metzler wrote:

> Hi,
> I was just wondering if anybody knows about CD-R reliability and how
> robust they are concerning damage from usage and transport.
> The reason I am saking is because I have gotten a large amount of
> CD-Rs from my brother in Germany. He sent me Mpeg files containing
> some of my favorite TV-series, which are not broadcast here in Japan. 
> Now I found that some of the Mpeg files on those CDs seem to
> deteriorate with time. I don`t know if this is caused by usage ( I
> don`t think so because I only watched them 2 or 3 times each) or the
> way are store them. Since my brother sends them by mail he doesn`t use 
> the jewel cases they came with, but uses thin plastic sheets (Is that
> the right word). They are sold by CaseLogik maybe you know them. 
> On some of the CDs there were already errors when reading the Mpegs
> when they arrived here, but some seem to develope more and more errors 
> the older they get. Is that something you have to expect from all
> CD-Rs. Has anybody else experienced such effects. I think the fact
> that Mpegs or the software that plays them are sensitive to such
> errors makes it possible to recognize them better than on data CDs.
> I is disappointing though. Not because I want to see the Mpegs again,
> thats ok, for most of the stuff once is enough, but because I also
> made backups of my research data on CD-R.
> Maybe you have to keep the stuff in the jewel cases.

Well, CDs are vulnerable to extreme temperatures and (obviously)
scratching... it might have gotten too hot in the plane over to Japan, or
too cold (from Germany to Tokyo, the plane would fly great-circle over
Siberia, right?).  CDs are vulnerable to cold, as well.  possibly the
expansion/contraction of the media under the temperature differential
caused very small cracks in the media that are causing the errors?

Or you could just have an older or slower CD drive.  Some of those don't
like reading certain CDR disks, it depends on the quality of the drive and
of the CDR media.  3M and Sony CDRs tend to work better in those drives
than the cheaper kinds.

--------------------------------------------------
Scott M. Stone <sstone@example.com, sstone@example.com>
               <sstone@example.com>
Head of TurboLinux Development/Systems Administrator
Pacific HiTech, Inc (USA) / Pacific HiTech, KK (Japan)
http://www.pht.com		http://armadillo.pht.co.jp
http://www.pht.co.jp	        http://www.turbolinux.com


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