View Full Version : Storing Data on CD's!

03-11-2003, 06:09 PM
The following is an extract from an article in the latest newsletter from
Fred Langa's Langalist,posted today!

Can't say Iv'e seen any other comments on this subject for quite some time.
Now wondering if all those mp3's of mine on Warehouse elcheapo blanks are OK?

Time To Check your CDRs

Almost three years ago, in "Is Your Data Disappearing?"
( http://www.informationweek.com/story/IWK20010719S0003 ) we discussed
the likely lifespan of burn-it-yourself CDRs--- an important
consideration when you're using CDs to archive data for long-term
storage. At that time, even the cheapest CD blanks were thought to be
good for at least 10 years after burning, with some premium CDR types
possibly good for as long as a century.

Those estimates were based on accelerated aging tests performed on the
various dyes used in CDRs or CDRWs: The dye layer is what actually
carries the data in a CD, and also is what gives the disk its
characteristic color--- blue, silver, green, etc.

But the conventional wisdom about CDR longevity was called into question
several months ago with a series of tests originally presented in the
Dutch "PC-Active" magazine and widely recirculated on English-language
web sites. Those tests suggest that many CDs may fail in as little as
two years!

That article sent many of your fellow readers (and me!) back into our
libraries of old CDs to see how they're holding up.


Rod ger
04-11-2003, 08:46 PM
I have not had any reading problems so far with SKC and Emtec from the warehouse using a Liteon*32.

Perhaps we could post good and bad results and burner/CD combinations
to get some idea of the problem.

04-11-2003, 09:19 PM
: The dye layer is
> what actually
> carries the data in a CD, and also is what gives the
> disk its
> characteristic color--- blue, silver, green, etc.
Those tests suggest that many CDs may fail
> in as little as
> two years!

I was thinking more of the old purple"Transonic", that you get from time to time at $16.95 for 20-25!
It's the 2yrs v 10yrs that is the worry!


Rod ger
04-11-2003, 09:49 PM
Are these the the only ones that have probems?? Do some burners "cook" better than others?? Are there bad combinations of burners and CDs???

08-11-2003, 12:02 AM
I suggest getting quality media, over cheap bulkpacks. If data is worth 50cent extra each CD used, its good enough to keep. Look back, how many CDs did you burn during the years, you still use frequently. Not many i guess...I store most my data on a external Maxtor , based upon the fact whats stored isnt worth to keep anyway.

Rod ger
08-11-2003, 08:01 AM
I think one of the premises of the article is that DESPITE dye aging tests CDs are dying(please excuse the pun).
Obviously cds made with poor accuracy and quality control will die quicker than others, but who's to know if price is determining factor.
If manufacturers thought their CDs were going to last a minimum of ten years for the lowest grade(cheapest dye) do you not think some would be labeling and charging their product as premium grade?
Or am I just a bit too cynical ??

09-11-2003, 06:16 AM
Now you've got me nervous. The oldest CD I've got that's readable is dated 5 November 2001. What was that about 'as little as two years....'?
One file on that disk (*.mpg) failed to read.

A couple of (slightly) older disks are not readable at all, but I know some of the first ones I did didn't write properly and maybe I erroneously kept the "coasters" (they don't have numbers felt-tipped on the upper disk surface, which makes me suspicious that they were failures.)

Maybe they were written with the old Adaptec (now Roxio) software that XP killed :-) It let you treat a CD-R like a large floppy, and drag-and-drop files to it, but seemed to be in a specific format that drives without the software wouldn't read. Got it bundled with the PC, and when I moved to XP, it demanded I update two full generations (and, naturally pay); so I let it slide.

Still ithe check was a nice nostalgia trip :-) And it showed me how much rubbish I used to indiscriminately fork across from my HD in those days.

If I wanted to (a) preserve some of the older stuff securely; (b) get rid of the stuff I don't want, I could probably reduce my drawer-full of disks to a half or less. But who's got the time?

There's got to be a service that will do bulk copying onto new media for the sake of preservation at least.


Odd thing is that there's one file on that oldest-readable disk dated 1995.
Must have been when the file was originally created. Which brings up another topic: Are there circumstances in which files written to CD retain their original creation (or acquisition onto HD) date rather than redating with the date on which you copied them?

Graham L
09-11-2003, 01:15 PM
I started saying that all the files in a software installation have their actual creation dates, but realised before I finished the sentence that all the files that matter are inside compressed archives. Except ... what do the uncompressed files look like? I have a feeling that since it's just a copy, the original creation date ought to be preserved. Any .ios file created will have 'today"'s date, but the component files should keep all their attributes, except for the read-only one. :D

It's always been fairly easy to force a particular date on a file when copying, but usually the original date has been kept, with all the other attributes.

Of course it looks as if some of these files should be given a write-only attribute. :D But nothing changes ... for a while people were making "backups" on " tapes. Those used an impossible bit density (something like 18000 bpi, whereas industry standard " tapes written on expensive drives in air-conditioned rooms peaked at 1600 bpi). Many of those QI es were unreadable immediately after being written; letalone after a few years. :_|