How to Choose CD/DVD Archival Media

Almost all computer users need to preserve data occasionally, and probably the most common method is to write the information onto CD or DVD data disks. For most computer users, preserving data for a year or two is sufficient. In fact, many people are only concerned with preserving data until next year's tax season. However, genealogists, historians, archivists, and a few others  are concerned with much longer preservation. We often think in terms of decades or even centuries.

Patrick McFarland has written an in-depth article that describes CD and DVD recordable media, explaining the various formats and their strengths and weaknesses. He points out that most of today's "record-at-home" CD and DVD disks will only last a few years. However, certain brands are expected to be useable for at least 70 years, and one manufacturer's products may last for up to 100 years.

McFarland explains the differences between "pressed" CDs (made by the thousands in a factory) versus "burnt" CDs (recorded one at a time on a computer). He then focuses mostly on CD and DVD disks recorded (burnt) on computers. His article describes the advantages and shortcomings of the different blank disks that you can buy in a local computer store, online, or by mail order. He also tells why DVD+R disks are much better than DVD-R.

The article ends with McFarland's recommendation for the best archival quality writeable CD and DVD disks. He even tells which brand he buys for his own archival storage.

I think that one part of McFarland's article should be required reading for all:

Unlike pressed CDs/DVDs, 'burnt' CDs/DVDs can eventually 'fade,' due to five things that affect the quality of CD media: sealing method, reflective layer, organic dye makeup, where it was manufactured, and your storage practices (please keep all media out of direct sunlight, in a nice cool dry dark place, in acid-free plastic containers; this will triple the lifetime of any media).

The article is liberally spiced with technical terminology, but most anyone can understand his plain English recommendations, given at the end. You can read this excellent article on Patrick McFarland's blog at: http://tinyurl.com/ycowgr

After reading McFarland's article, I ordered 100 archival-quality CD disks for my own use. How long do you want your information to last?

Comments

[Infinite Ancestors]

It's not clear what Mr. McFarland's expertise or motivations are in making his recommendations. For example, why does his link to SuperMediaStore.com not go there directly, but rather through a series of adware/tracking links? I had to temporarily disable blocking of the following domains in a malware blocking feature I use, just to be able to click through his link to the store: jdoqocy.com, apmebf.com, & qksrv.net . Suffice to say that he may likely have a monetary interest in his recommendation in the manner he made it, so take it for what it's worth.

There may be some techincal reasons why DVD+R is better than DVD-R, but everything I have read in the past indicates that DVD-R has a higher success rate with more burners and players. I use high-quality brand-name DVD-R media for all short-life needs (but do use DVD+RW for short-life rewriteable due to its better editing features).

As far as longevity goes, there is no definitive data yet, but gold (e.g., Mitsui MAM-A) recordable DVDs are my choice over the TY media, though in practice there may be little predictable difference. Both should last longer than I will, given reasonable care.

Here is another perspective on archival-grade recordable media:
http://bonus.ppmag.com/2006/04/answers_to_your.html

[Sally]

The author mentions a certain online forum in his article, and there are comments from others that this particular forum has a VERY strong brand loyalty to TY. I didn't bother to click on any of the links, but I find it interesting that the author might be pocketing an affiliate fee. Hmmm.

For me, I take my cue from the Wisconsin Historical Society Archives (www.wisconsinhistory.org) and use Mitsui MAM-A gold CDs exclusively. And please keep in mind that successfully preserving digital data involves not just the media on which it is stored, but the hardware and software used to transform those 1's and 0's into a readable file.

Over the past four years, Cornell University Library has asked workshop participants from around the globe to answer the following question:

"Are there any digital materials in your holdings for which you lack the operational and/or technical capacity to mount, read, and access?"

A whopping 70% answered yes or don’t know. (!!) So while I might not be able to give you spectacular examples of digital obsolescence, rest assured that the problem is real. Cornell created a pilot project to rescue data on obsolete machines and media. Read the free report here:

Digging Up Bits of the Past: Hands-on With Obsolescence
http://www.rlg.org/en/page.php?Page_ID=20987#article1

-Sally