Why shouldn’t you use CDs as a long term storage medium?

Why shouldn’t you use CDs as a long term storage medium?

Response:

This was a question that was asked by two of my clients over the summer. It reminded me of two articles I wrote in 2004 outlining some of my reservations on using cds for long term data storage and also a recent article; ‘Do Burned CDs have a Short Life Span?’ by John Blau in ‘PC World’, January 10, 2006 issue.

I personally use CDs as a backup media, and I burn CDs for my clients on projects that I have completed. They are backups only as my clients also retain a full set of the paper documents for the project. I do not consider anything I do as having long term retention value for my personal collection and I do not make backups of client records that have a long term retention requirement. But, if I did, two of many things that I consider are:

Media Type:

Compact Disks (CDs) are optical media. Guidelines from different articles PUBLISHED on the subject state THAT CD-R or CD-R/W MAY be used for long term storage with A life expectancy of CD-R between 100 to 200 years under optimum conditions AND CD-R/W should have a life expectancy of 25 years or more under optimum conditions. I recommend reviewing an excellent article by Fred R. Byers on the “Care and Handling of CDs and DVDs, A Guide for Librarians and Archivists”, published by the Council of Library and Information Resources and the National Institute of Standards and Technology, October 2003 www.clir.org/pubs/reports/pub121/pub121.pdf ).

Not all CDs are equal or of archival quality. You should also check the archival quality of the media sold by the manufacturer. A Dutch PC-Active magazine did an extensive CD-R quality test on the different CD-R brands and found that some had become completely unreadable (http://www.cdfreaks.com/news/7751 ) within 3 to 7 years.

In a discussion on the subject of standards on the records management listserv one person wrote that “the only standard that may pertain is “ANSI/NAPM IT9.21-199 Life Expectancy of Compact Discs (CD-ROM) – Method for Estimating, based on effect of temperature and relative humidity. I know I do not meet this standard. Do you? Does your vendor? If not, you have one of many problems with storing the information on a CD.

Migration:

Besides the longevity issue another important aspect of maintaining business information on CDs/DVDs is the long term problem with migration. Over the summer I have discussed migration with two individuals who are maintaining and/or contemplating maintaining their business records on optical disks. I asked the question; “How are you planning to manage the migration issue?”. One of the individuals was not aware of the longevity issue, while the other individual was aware and had a migration plan in place to migrate data every 7 years. Neither individual was aware of the article I mentioned above by John Blau, stating that; “Unlike pressed original CDs, burned CDs have a relatively short life span of between two to five years, depending on the quality of the CD”. He further stated “There are a few things you can do to extend the life of a burned CD, like keeping the disc in a cool, dark space, but not a lot more”. If you are working in the public sector I would recommend checking with your State Records Management Department for guidance.

You might also check out the National Archives and Records Administration’s website on optical media at http://www.archives.gov/records_management/index.html, then:
Click Records Management Frequently Asked Questions
Click FAQs About Optical Media

I also recommend that you add this website to your Favorites and save for future reference.

I still advocate using CD’s where appropriate, but I am mindful of the problems and costs that you may incur in the long term. If you are considering a scanning project from paper into an electronic format you need to closely review the project to insure that the cost does not exceed the benefits.

Enjoy….BobDalton, CRM of Dalton Consulting

Note: My thanks to Barbara Werelius, Records Manager and public records guru at Tacoma Public Utilities, for her assistance in the development of this article.