In our quest for a greater understanding of computers and the Internet, let’s put another computer myth into the trash bin. This week’s column will be devoted entirely to:
Myth No. 4: “CDs last forever.” Introduced in 1980, the Compact Disc (CD) presented digitally recorded music to the masses, and permanently changed the music industry. Subsequent usage and research brought the notion that CDs would be a great way to store, not only music, but digital computer files and programs, as well. This brought about the CD-ROM (Compact Disc-Read Only Memory), which is what you get when you buy a computer program or game on a commercially produced CD. Then, in 1988, Compact Disc-Recordable (CD-R) technology brought to individual computer users the ability to record (or, “burn”) their own CDs, marking a major milestone in the “computer revolution.”
CD technology also brought bloated claims of shelf life and longevity, which were quickly dashed as early CDs literally began to fall apart due to unproven materials being subjected to unexpected rigors and conditions. Dramatic improvements in CD materials technology have been made, bringing us the fairly reliable and inexpensive product we enjoy today.
However, nobody really knows how long CDs can hold up, since the technology itself is relatively young. Current shelf life estimates are based on accelerated age testing techniques performed by CD manufacturers, which, according to some pundits, do not include many real-world conditions that might shorten a disc’s lifespan. The materials used in the manufacturing process also play an important part in a discs longevity. Those cheap, 100 for $10 bargain CD-Rs simply aren’t going to hold up as well as more expensive, archival-quality discs.
That said, the shelf life of an unrecorded CD-R or CD-RW (Compact Disc-ReWritable) is estimated at between 5 and 10 years. Manufacturers claim that recorded CD-Rs can last from 50 to 200 years, and CD-RWs are rated at 20 to 100 years. The Library of Congress and the National Institute of Standards and Technology have conducted studies suggesting that very few commonly available brands of CDs will actually be able to meet these optimistic projections.
Proper care of your discs is vital to their longevity. Scratches can render your discs unusable. CD-Rs, CD-RWs, and even recordable DVDs use a layer of special dye that actually holds the recorded data, and this layer is sensitive to visible-light wavelengths. So, don’t leave your discs lying about exposed to light, especially sunlight.
Certain inks and solvents can also ruin discs. Use water-based permanent markers for writing on your discs, and never use ballpoint pens. Stick-on labels can cause problems if not centered properly on the disc, as they can cause an unbalanced condition in the CD drive, ruining the disc, and possibly ruining the drive, as well. When stored, your discs will last longest in cool, dry and dark environments. Keep these things in mind when making those CDs of photos for your great-grandchildren to enjoy.