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#1
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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! |
#2
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CDR Longevity
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 |
#3
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CDR Longevity
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/ |
#4
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CDR Longevity
.. --------------------------------------
Mike Richter, were you born with "Scam Artist" emblazoned on your face? -------------------------------------- http://tinyurl.com/6eldj (No Mikey S-lickers have been able to prove ANY of the above is a LIBEL) ( ) ( -- despite Mikey claimed to have proof of misquotes !! ) ' 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 |
#5
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CDR Longevity
"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 |
#6
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CDR Longevity
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 |
#7
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CDR Longevity
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 |
#8
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CDR Longevity
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 |
#9
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CDR Longevity
"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 |
#10
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CDR Longevity
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/ |
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