[ccp4bb]: Storage media revisited

[Morten Kjeldgaard <mok@imsb.au.dk>]

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Like Derek, I have also looked at DVDs for long-term data storage.

There are a number of unclarified issues wrt DVD data storage that
complicate the discussion of DVD as a medium for long-term storage. First
of all, there are six different formats for writing DVDs: (2*DVD-R,
DVD-RW, DVD-RAM, DVD+RW, DVD+R). Some of the newer DVD writers are said to
support several of these formats, but which format will survive depends on
how the market evolves. Apple supports DVD-RW in the Mac while most others
are going with DVD+RW.

The DVD demystified FAQ (http://www.dvddemystified.com/) is a good place
to get information, although it mostly deals with DVDs for movies.

While most of us are probably fed-up with DAT tapes, perhaps you were a
bit hasty to dismiss tapes for storage, Derek! A lot is happening on that
front these days, but again we are faced with a multitude of different
formats. However, all of them allow storage of at least 10Gb, which is
sufficient for several synchrotron datasets. The ADR2 format from
http://www.onstream.com (a Philips subsidiary) is especially interesting
since it is a rather inexpensive solution, has high reliability, capacity
up to 120Gb and boasts Mac and Linux support.

IMHO the DVD vs. tape discussion for diffraction data storage is a tie. It
is a PAIN to master a DVD, there is no good software for Linux, you need
disk space to hold the data _twice_, and it is slow. Once mastered, you
can course read the data directly from the DVD. There is lots of software
for writing tapes, it is rather fast and painless, but if you need to
re-process your images, you have to reload them from the tape. Both DVD
and tapes are fragile media, the DVD can get scratched, and the tape can
turn into linguini.

The cost of the media is not the most important parameter, it is trivial
considering the value of a dataset (!!!), including all the man-hours that
went into expression, purification, crystallization, the value of the
sychrotron time, etc, etc. You don't wanna know this number... :o)

These were my 0.02 Euros = $ 0.0202519 worth...

/Morten

-- 
Morten Kjeldgaard <mok@imsb.au.dk>
Department of Molecular Biology, Aarhus University
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