Re: [R] Q: Suggestions for long-term data/program storage policy?

From: Prof Brian Ripley <>
Date: Tue 11 Oct 2005 - 21:04:38 EST

On Tue, 11 Oct 2005, Alexander Ploner wrote:

> we are a statistical/epidemiological departement that - after a few
> years of rapid growth - finally is getting around to formulate a
> general data storage and retention policy - mainly to ensure that we
> can reproduce results from published papers/theses easier in the
> future, but also with the hope that we get more synergy between
> related projects.
> We have formulated what we feel is a reasonable draft, requiring
> basically that the raw data, all programs to create derived data
> sets, and the analysis programs are stored and documented in a
> uniform manner, regardless of the analysis software used. The minimum
> data retention we are aiming for is 10 years, and the format for the
> raw data is quite sane (either flat ASCII or real

You are intending to retain copies of the OS used and hardware too? The results depend far more on those than you apparently realize.

> Given the rapid devlopment cycle of R,

I think you will find your OS changes as fast: all those security updates potentially affect your results.

> this suggests that at the very least all non-base packages used in the
> analysis are stored together with each project. I have basically two
> questions:
> 1) Are old R versions (binaries/sources) going to be available on
> CRAN indefinitely?

Not binaries. The intention is that source files be available, but they could become corrupted (as it seems the Windows binary has for a past version).

> 2) Is .RData a reasonable file format for long term storage?

I would say not, as it is almost impossible to recover from any corruption in such a file. We like to have long-term data in a human-readable printout, with a print copy, and also store some checksums.

> I would also be very grateful for any other suggestions, comments or
> links for setting up and implementing such a storage policy (R-
> specific or otherwise).

You need to consider the medium on which you are going to store the archive. We currrently use CD-R (and not tapes as those are less compatible across drives -- we have two identical drives currently but do not expect either to last 10 years), and check them annually -- I guess we will re-write to another medium after much less than 10 years.

Brian D. Ripley,        
Professor of Applied Statistics,
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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