Are your CDs dying?

Are your CDs dying?

Summary: Perhaps you thought that since music CDs are mechanically stamped and sealed in tough plastic, they'd last forever. Wrong! Some may already be dead. Here's why.

TOPICS: Storage

Take two copies of the same manufactured CD from 1987 and subject to extreme heat and humidity in an environmental test chamber. Should turn out the same, right? No:

Photo: Library of Congress

The one of the right is totally destroyed, while the one on the left is still playable. Why?

Commercially reproduced CDs — the kind from major music labels — are manufactured using a physical stamping on the plastic which is given a metallic coating to reflect the laser light - a physical imprint on the media. Writable CDs and most writable DVDs and Blu-rays use a chemical organic dye layer that is inherently unstable and will often die within five years.

According to the Library of Congress, even commercial CDs made in the same year by the same company can have very different production processes leading to startling differences in failure rates and modes. For example:

  • Edge rot. Oxygen seeps through the plastic and reacts with the metal layer.
  • Bronzing. Corrosion due to pollutants in the air.
  • Laser burn. Player lasers also differ and some may shorten CD life.
  • Mis-handling. Bad scratches, yes, but also stickers and permanent marker writing on top.

The Storage Bits take
If you haven't already ripped your treasured CDs yet, now's the time! Whether you pick a lossless codec or high quality mp3, you can't rely on a commercial CD's quality to protect music you love.

The LoC is researching this issue, in line with their mission to store and protect American history, through their Center for the Library's Analytical Scientific Samples (CLASS). They're putting together a database of scientific information on many kinds of media, including CDs.

If there's something you want to save for the long term, consider writing it to an M-disc, whose non-organic write layer can sustain remarkable amounts of abuse (see Torture testing the 1,000-year DVD). It's the only media I'd trust for long-term digital storage — and only if I store copies in different places.

Comments welcome, of course. And a hat tip to the excellent Atlantic magazine for a piece on this issue.

Topic: Storage

Kick off your day with ZDNet's daily email newsletter. It's the freshest tech news and opinion, served hot. Get it.


Log in or register to join the discussion
  • Data CD Discs. will go the same way as the Floppy Drive….

    Five years ago I relied heavily on Discs. These days most the time I use USB 2.0/3.0 Flash Drives.

    So yes are far as Computer Data Discs. are concerned I believe the days of the CD are numbered given that many units no longer come with Disc. Drives.

    However I think the CD will hang on in the Music Industry for a good while longer.
    • Thinking that flash is safe

      is like having unprotected sex, and only thinking about the fact that your partner has been sterilized - you are completely ignoring other things [bad] which can happen.

      I have had several top-flight, name brand flash drives go bad, when they were never subjected to anything above room temperatures, and well-within their warranty period. I have also had a couple go flaky, where, depending [? on the phase of the moon ?] they would, or would not read.
      • One good "ZAP!" and you're doomed!

        A coworker of mine put his flash drive in the USB port one day and we saw a quick flash of a spark on the connector. Whoops! Dead drive. All data gone, and some of it was his wife's data.
        • None

          No memory storage is forever. If you want data to be available, you need to have it reside in multiple places.
          • Ever?

            Write it in Cuneiform on a clay tablet.
            Bake it well, and it will endure for as long as you require...
            Michael Kingsford Gray
  • Music CD players are designed to be "error tolerant".....

    .....unlike data CDs where every bit must be recovered perfectly.
    Don't flash drives and hard disks also degrade over time?
    I have at least 5 ripped copies of all my music CDs and have noticed that some tracks become unplayable by the computer over time!
    • Not every bit needs to be recovered perfectly

      CDs have error correcting codes built in, so a scratch doesn't necessarily destroy a music or data disk. You can lose a number of bits and the ECC will recover the data.

      R Harris
  • CD longevity

    For long term archival here is how I rank various digital technologies in terms of longevity:

    1. Magnetic tape
    2. Stamped optical media
    3. WORM optical media
    4. HDDs always on

    As for M-Discs that's a wildcard. Check back in about 10 years.
    And never ever flash based storage. This includes CF, USB sticks, ssd's etc.
  • Been hearing this all for years now.

    And I still have discs I bought in 1985 that play just fine. Same with players from that period that still work. That's 29 years and counting.

    Part of the problem was that when CDs came out, we were assured they were indestructible. But some experiences early on (like a friend who lost some out of a backpack while bicycling) showed that was marketing B.S. As for the aging issues (like "rot" which is an oldie-but-goodie) a lot of it can be traced to misuse - especially on the label side. Most people don't consider that the lacquer and decal are the only protection on that side - and it's a lot less durable than the plastic side. Ironically, if the spec had called for a thin plastic (instead of lacquer) coating on the label side, the durability would have been much higher. Too late now. But honestly, prevent scratches (especially on the label side), no stickers or markers with alcohol that could eat the coating, and keep in the same environment you are comfortable in (no saunas, hot or cold cars, and wasted teenagers) and the discs can last a good long time. Funny, weren't those the SAME as recommended for vinyl phonograph records too???
    • Marketing

      Compared with vinyl records CDs were more robust: it wasn't too long after their US introduction that we heard a life expectancy of 20-30 years.

      As to care instructions, heat, water, the environment, deformation due to poor storage are factors that wear out any thing.
      • Not sure I agree there

        I have numerous CDs that have become unplayable, and no vinyl records that have become unplayable, many of which are older than me (47).
    • Vinyl vs CD

      Everytime on played a vinyl record one was unintentionally damaging it because of the mechanical pickup with the stylus. Vinyl had a relatively short lifespan based on number of plays and the quality of the turntable. CD, in theory, could have an infinite life because the laser, in theory, was not damaging the surface. So the number of plays should not be a factor.
      • Except

        The ink that makes up the dots can degrade over time so CDs that you write yourself have a 5-year lifespan (your mileage may vary). Part of it is how you keep the CDs. Staying away from heat and light helps. Music CDs that you buy have actual "holes" pressed into the metal. They are totally different.
        • My mileage is quite different

          I purchased my first CD burner in 1997. I used it to back up data and to transfer some of my LPs to CD. So far, I've seen no issues. Granted, I don't run them that often and I keep them in a cool, dry environment. I'm also careful how I handle them (or any disc). Doesn't mean they aren't deteriorating, but so far, no sign of trouble.

          By the way, Blu-Rays not only have a scratch resistant read surface, the label side has a layer of plastic, making them more resistant to damage. I don't think much of Sony, but they and their partners do know how to develop a standard.
    • Only an idiot

      believed that "7th row, forever" crap handed out by Sony - and I was as big a Sony fan at the time as anyone could be.

      I was, however, a person who read, and knew that the Reed-Solomon CIRC was NOT a panacea, and that competent reviews were showing differing values for the amount of recovery that could be had from different CD players.
  • No fails so far.

    I don't abuse my media and I have cd's nearly 30 years old that play perfect. As a side note, I have some old records that are over 60 years old and still play fine.
    I figure since I'm already old that if my media lasts maybe 10 - 20 years that's good enough for me.
    • 1st, it's "play perfectly"

      and second, though vinyl IS capable of greater resolution than optical disc, it is also affected by mechanical degradation much more than optical media. Every time one plays a record, it is another small removal of what was once there.

      Also, you don't KNOW that those CDs play perfectly, you only know that they are playing at a rate at which the error correction is still inaudible - too bad we no longer have audiophile CD players, which show how much of the time error correction is functioning - many people would, no doubt, be aghast at the results of a casual listen to their "pristine" CDs.
      • Chrome, that's typical "audiophile" BS

        Why would you want to go out of your way to find out that there are errors, whi9ch are being corrected, but at a rate that renders them inaudible?

        It's typical BS thrown out by self-styled audiophiles - similar to those who claim to be able to hear frequencies higher than 20kHz or lower than 20Hz.
        • So you can tell how they are holding up

          We used to run diagnostics on mainframe computer memory and replace it when ECC errors got too numerous or too close to being an uncorrectable error. The same should go with CDs. It is not a foolproof method, but it is better than blissfully proceeding until you've lost everything.
      • What about computer drives?

        I would imagine software is available that tells you the error rate when reading from a disc. I may even have some, without knowing it. Granted, error correction on a computer drive is better than stand-alone players. But it still should be possible to track any degradation.

        Note that the CD could be *playing* perfectly, if the error correction is doing its job. If the output from the DAC is the same as for a pristine disc, then any errors are irrelevant. Any continued deterioration, if present, is another matter.

        Vinyl is capable of greater resolution than CDs? Really? The reality is that LPs had a noise floor of about 45-50 dB, which made any "superior" resolution inaudible. Not to mention the issues playing content with heavy bass. DBX LPs came close to CDs, but they were few and far between. I only ever saw two, both of which I purchased and enjoyed thoroughly pre-CD days, using an encode/decode box. But two records does not a collection make. And it's a fair amount of processing, which a "purist" would object to having.

        Anyway, are you an English teacher? Or a grammar cop? I knew what he/she meant, you knew. Is it really worth commenting on what might even have been a result of mis-typing. I could mention the run-on sentence that comprises your second paragraph.