CDR Longevity

Is there a rule of thumb as to how long a music CD-R might last that
hasn't been subjected to any kind of "abuse" (scratches,extreme temps,
direct sunlight,chemicals,etc)?

I've read that CD-Rs do have a finite lifespan.If this is true,what
signs (if any)
are there that one has started to deteriorate?

Thanks!

jason wrote:

I've read that CD-Rs do have a finite lifespan.If this is true,what
signs (if any)
are there that one has started to deteriorate?

You can't read it. All or part.

--
dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

dadiOH wrote:
jason wrote:


I've read that CD-Rs do have a finite lifespan.If this is true,what
signs (if any)
are there that one has started to deteriorate?


You can't read it. All or part.

Again, the news server I use omitted the original post, but since
dadiOH's reply is incomplete, I'll try to cover both.

The sign of deterioration is increase in correctible errors. When they
become uncorrectable, the disc is no longer readable, usually losing the
largest files first since failure is random. If one begins by writing
with a known, low (or zero) error rate, then over time a retest may show
correctible errors creeping in. When that happens, dub the disc before
it fails.

For archiving, it's wise to make two masters, preferably on different
media. Checking one copy every few years and alternating copies tested,
you are almost certain to have a good one when the other starts showing
errors. Obviously, it's wise to get low initial error rates and to know
what they are by testing each major batch of media before committing to
its use. However, for ordinary home use that much effort is unnecessary.
When you find one of your saved discs is acting up (reading slowly, for
example), it's time to check error rates and to replace the other
backups you have from that batch of blanks.

The rated life of a well-written CD-R is of the order of decades. In
practice, poorly written media can have life expectancy of a few years
or less.

Mike
--

http://www.mrichter.com/

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"Scam Artist" emblazoned on your face?
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(No Mikey S-lickers have been able to prove ANY of the above is a LIBEL)
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'

jason wrote:

Is there a rule of thumb as to how long a music CD-R might last that
hasn't been subjected to any kind of "abuse" (scratches,extreme temps,
direct sunlight,chemicals,etc)?

I've read that CD-Rs do have a finite lifespan.If this is true,what
signs (if any)
are there that one has started to deteriorate?

Thanks!

DISC LONGEVITY
http://www.osta.org/technology/cdqa13.htm

Long term stability study on CD-R and DVD-R medias
http://www.itl.nist.gov/div895/gipwg/StabilityStudy.pdf

"XP" wrote in message
...
On Thu, 17 Nov 2005 10:00:38 -0500, jason wrote:

Is there a rule of thumb as to how long a music CD-R might last that
hasn't been subjected to any kind of "abuse" (scratches,extreme temps,
direct sunlight,chemicals,etc)?

I've read that CD-Rs do have a finite lifespan.If this is true,what
signs (if any)
are there that one has started to deteriorate?

Thanks!



Verbatim Metal Azo have a 100 year life span and Mitsui Archival CD's
have
a 300 year life span.

One needs to be a little naive to accept such figures. It's not that they
couldn't be accurate but how on earth would anyone know.
Dave Cohen

On Fri, 18 Nov 2005 14:58:32 +1300, XP
wrote:

Verbatim Metal Azo have a 100 year life span and Mitsui Archival CD's have
a 300 year life span.

I'm not so sure about that. The deterioration rate of some of those
Mitsui Archival CDs (that have been stored under perfect conditions) that
I burned 125 years ago is projecting out to unrecoverable errors at 210
years.


--
N

XP wrote:
On Thu, 17 Nov 2005 10:00:38 -0500, jason wrote:

Is there a rule of thumb as to how long a music CD-R might last that
hasn't been subjected to any kind of "abuse" (scratches,extreme
temps, direct sunlight,chemicals,etc)?

I've read that CD-Rs do have a finite lifespan.If this is true,what
signs (if any)
are there that one has started to deteriorate?

Thanks!



Verbatim Metal Azo have a 100 year life span and Mitsui Archival
CD's have a 300 year life span.

Want to buy a bridge?

--
dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

dadiOH wrote:
XP wrote:

On Thu, 17 Nov 2005 10:00:38 -0500, jason wrote:


Is there a rule of thumb as to how long a music CD-R might last that
hasn't been subjected to any kind of "abuse" (scratches,extreme
temps, direct sunlight,chemicals,etc)?

I've read that CD-Rs do have a finite lifespan.If this is true,what
signs (if any)
are there that one has started to deteriorate?

Thanks!



Verbatim Metal Azo have a 100 year life span and Mitsui Archival
CD's have a 300 year life span.


Want to buy a bridge?

Practically all of which require very major repairs or even rebuilding
after 300 years.
Allen

"XP" wrote in message ?

Verbatim Metal Azo have a 100 year life span and Mitsui Archival CD's
have
a 300 year life span.

Will there be anything to read the CDs in a 100 years time, will the blue
lasrer DVD drives read a CD?

Paper tape was in use about 30 years ago, how many readers are about now?

Regards, Malcolm

Malcolm Young wrote:

Will there be anything to read the CDs in a 100 years time, will the blue
lasrer DVD drives read a CD?

Paper tape was in use about 30 years ago, how many readers are about now?

A legitimate question, though not one likely to be critical to the Subject.

Note that a reader for paper tape can be cobbled together quite easily
with no information but the tape itself. Indeed, logic alone would
supply all that was needed for an alien after Armageddon to convert such
a tape to text in decipherable form, though whether that text (which
might be an assembly program) is meaningful would depend on decryption
and translation skills.

An analogue recording - say a shellac disc - is a bit trickier since
speed and interpretation are issues. But speed is an issue with any
player and disc and if the audio signal is not recognized as audio,
perhaps the alien will read it optically. Basically, though, the
analogue disc is only a bit harder to deal with starting from complete
ignorance of its 'language' than is the paper tape. (That's why that
format was used on the Voyager disc.)

However, interpreting a CD-DA is another matter altogether, requiring at
least the specifications in the red book. The audio information is
sampled and digitized, the bits are organized and expanded, the result
has additional material added for ECC and subchannels, and the whole is
encoded with expansion to the disc, written and read in analogue and
gated to make digital information. The process would be tedious in the
extreme without the redbook as a guide.

So if there is no player available or constructable, the CD would be
useless, a curious artifact with no readable information. That has
already happened to many other formats of modern times; I've no idea how
one would read a V-Cord videotape today and many thousands of digital
data tapes are in storage for lack of a reader. Not so long ago, the
last known IBM 7094s extant were at a U.S. Air Force facilty to run
programs written for them and not worth translating to modern computers.

How long will CD players be around? It's hard to say, but I'd guess that
it will be possible with some diligence to recover information from a
disc a century after it was written - if the information is still there.
That was the original question, I believe, and one worth answering. If
the incentive is great enough, players will still be available as they
are today for Berliner discs of a century and more ago.

Mike
--

http://www.mrichter.com/