Re: [ccp4bb]: DVD archving - thanks

[Mischa Machius <Mischa.Machius@utsouthwestern.edu>]

> the data are guaranteed for 1 year.

Wow, that is a bit pessimistic! Some companies project the lifetime of their DVD-Rs to be about 100 years. Granted, they don't _guarantee_ 100 years, but I couldn't find clear guarantee statements from tape manufacturers either. Guarantees don't help if your media are bust. You may get your money back, but not your data. 

It clearly depends on the quality of the DVD-Rs. We do all our image archiving on DVD-Rs on Macs (we also keep the images around for quite some time on hard disks on a terabyte server; bzip2 works wonders). Although we didn't buy the best quality media, we have verification errors in only about one out of ten DVD-Rs. The convenience beats tapes any time. One can actually give DVD-Rs to collaborators who don't have a DDS4 tape drive. In addition, archiving on tape seems to be a huge waste of money, as tapes are good for backups, but not really for archives.

We constantly try to adapt our archiving strategy to the current state of technology and crystallography. It is no longer necessary to keep images for 20 years. At most 2-3 years sounds more realistic. DVD is certainly suitable for that. In 5 years, there may be a better technology, who knows. At the moment, we are happy with DVD technology.

MM


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Mischa Machius, PhD
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UT Southwestern Medical Center at Dallas
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