CD and DVD Media Quality
Back in the 80's, when the first CDR discs became available, the manufacturers stated that the data life on the recordable CD was in excess of 40 years. In the 90's when DVD media became available, the manufacturers said that the data life would be at least 100 years. Quite how they know that we don't know, however there have been a few occasions recently when the media have published scare stories about CD or DVD failure that will destroy your information 2-3 years after it is written.
In 2003, it is believed that more than 7,100 million CD-R and more than 400 million DVDR discs were manufactured sold and it is worrying that this media is being used to archive virtually everything. If these discs are the only place that you have priceless, irreplaceable, family photos and videos, company data and other important information, it is very concerning.
So What Are The Facts?
Have I Got Good Media?
Option 1: Write some CDR or DVDRs, then wait about 25-50 years and check
if they still hold the correct data
The first is impractical however some of the first discs produced and written to in Japan still hold valid data. The second provides only theoretical limits and doesn't’t take into consideration how you use, handle and store the media.
Between the CD-R discs produced in the early 80s, to today’s double layer DVD+R DL discs there has been considerable progress in write performance, capacity, quality and obviously price. Through using the test procedures of the International Standards Organization, quality media manufacturers have been able to document data life-spans ranging from 50-200 years. Please bear in mind there are massive differences between low budget media operations and quality media manufacturers. In addition variations in manufacturing methods, materials and processes/procedures can dramatically affect the data life of the media you use.
Understanding CD and DVD Media Construction
Most people consider DVDR discs little more than overgrown CDR and while they are similar, they are also quite different.
Writable CD and DVD discs start with a piece of polycarbonate substrate onto which very precise grooves are molded. A dye layer is then precisely applied to the substrate followed by a reflective layer and one or more protective layers. A few of the media leaders have initiated the policy of applying two very resistant layers for added data protection when the discs are used, handled and stored.
Because of the faster read/write performance users expect, the leading manufacturers have developed new stamper technology for optimum groove shape and ultra-precise molding technology. The molding is critical because disc flatness is extremely important when the media must be rotated at extremely high speeds – 52x for CDR and 16x for DVDR.
There are also confusing and conflicting claims and consumer beliefs as to which media is best for data retention of 30, 50, 100 years – green, gold, blue dye or gold/silver reflective layer. It is somewhat immaterial today. Leading manufacturers such as Ritek and Traxdata have developed advanced, stable and reliable dyes and reflective materials that will virtually eliminate data loss during the high-speed read/write processes and subsequently enhance longevity.
One of the most common causes of problems are delamination and oxidation, which usually occurs at the outer edge of the disc and is often the result of the adhesive not being properly applied and cured during the production process. This usually happens when manufacturers use equipment that is 2-3 generations old and the least expensive materials possible to produce the cheapest discs.
Take Care of Your Media
We have put together a few tips for handling media:
What you can do:
Do not do this...
You Want Reliable Media?
We at BBDiscs only sell GRADE A media from leading manufacturers such as Traxdata, Verbatim, Taiyo Yuden, Ritek and TDK. We do not import cheap media from the far east and buy either direct from the manufacturer or from an authorised distributor. We are not the cheapest around, however we are the most reliable. Take a look at our store for more information on the products that we have available right now.
Thanks for reading, if you have any questions on this article please drop us an email.