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Hello, Steve and Stevie,

I have been using the MAM-A Gold DVDs since they came out and am 
pleased with them, but the last time I checked to answer Steve's 
question, MAM-A's attorneys are allowing them (or at least did allow 
them) to claim a 300 year life expectancy for the gold CD-Rs. The 
gold DVD-Rs I think have only been claimed at an 80-year life expectancy.

The one thing, however, that I think we've learned from tape is that 
in highly complex chemical products, the anticipated failure modes 
and failure stimulii are not always the ones that will bring on 
end-of-life conditions.

We have also seen how batch-to-batch variations in tape can affect 
the tape's longevity.

Both of these lessons are instructive to the CD/DVD marketplace.

For many of us, redundant RAID-5 or better arrays (i.e. two arrays in 
different locations), which can be managed and report errors seems to 
be a superior solution to more pieces of chemistry sitting on a 
shelf. Mixing one or more RAID arrays and LTO tape is also a good choice.

I'm not really sure that, given the published life expectancy of the 
MAM-A gold media, that the media will be the first link in the chain 
to go. 80 years is pushing readability of "ancient" technology as 
complex as DVD and CD. However, that all depends on when the 5-inch 
optical disc drops out of the mainstream. It may be around for 60 
more years, so in that case, the 80 year life is meaningful, but if 
it reaches end-of-life in 20 years, then keeping existing drives 
running for an additional 60 years will be problematic.

Yes there are many pros and cons to each solution, but I see DVDs 
more as short-term storage of files for clients who will be 
developing a trusted digital repository in the foreseeable future. I 
prefer to send gold CD-Rs to clients who are unlikely to create a 
trusted digital repository in the foreseeable future. However, if the 
client has high fidelity material that can benefit from 
greater-than-CD-quality transfers, then we're stuck with gold DVDs, aren't we.

CD delivery is the most costly, while downloaded files with MD5 
hashes is the least costly and fastest, with individual hard drives 
being an alternate "envelope" for delivery of files.

No easy solution, but nothing is permanent.

Regards,

Richard


At 02:55 PM 2009-06-30, Stevie Duncan wrote:

>         We have done quite a lot of testing with many different types of DVD
>stock and have found the MAM-A Gold Archival DVDs to be extremely reliable.
>We have not done any specific testing as far as longevity, but the company
>test info is here:
>http://www.mam-a.com/technology/technical_papers/documents/longevity.html
>
>-----Original Message-----
>From: Association for Recorded Sound Discussion List
>[mailto:[log in to unmask]] On Behalf Of Steven Smolian
>
>Is there a reliable recordable DVD for long term storage, independently
>tested?
>
>How does this compare with the anticipated lifespan of gold-reflective CDs?




Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.