Dear Richard That's right. No change since 1.0 has so far passed beyond being "provisional" since we didn't definitely agree how to do that. I am not strongly in favour of provisional status myself, but others have argued strongly for it previously. I think there is a good argument that we should try hard to avoid making a mistake which we have to reverse, because data lasts forever, and if data were written with a flawed standard, it would forever be a nuisance. Of course in principle this can be detected and perhaps worked round using the version from the Conventions attribute, but in practice I suspect this attribute is not normally written scrupulously correctly, nor inspected by analysis software. So we should be careful, and that means a "cooling-off" period during which data is at risk of being invalidated if it uses a provisional convention is a reasonable safeguard, but it should not be a long period - months, not years, I would say.
Best wishes Jonathan ----- Forwarded message from "Hattersley, Richard" <[email protected]> ----- > Date: Tue, 18 Mar 2014 09:05:36 +0000 > From: "Hattersley, Richard" <[email protected]> > To: "Gregory, Jonathan" <[email protected]>, > "[email protected]" <[email protected]> > Subject: RE: [CF-metadata] Editing/publishing workflow > > > I'd like to propose changing the rules. That's something the conventions > > committee can agree, I believe. I would suggest the simplest possibility, > > if we wish to retain provisional status, is to specify a time. We could say > > that, after one year from acceptance or when the next version of the > > conventions document is published, whichever is later, a change becomes > > permanent. What do you think? > > The more I consider the concept of "provisional status" the more it concerns > me. What does it actually mean for a netCDF file to use a particular > "Conventions" attribute value? How can one tell what is still in provisional > status? What version should data writers be using? I've checked back through > 1.3, 1.4, 1.5, and 1.6 and they all still contain sections marked as > provisional. Using the analogy to software versions that has been raised > elsewhere, the CF convention versions are essentially pre-release versions, > e.g. 1.6-beta, and are not suitable for production use. > > I would argue that the simplest possibility is to drop the "provisional > status" concept. Identifying and resolving problems should happen during the > discussion of the modification and its subsequent application to the > conventions document. > > If a further flaw, ambiguity, etc. is subsequently discovered prior to the > publication of the next version of the conventions then it can easily be > resolved at that time. > > If a problem is discovered after the publication of the next version then a > correction must be applied and published in a *new* version. That version > could be a "bug fix" version (e.g. 1.6.1) or it could just wait for the next > normal release, e.g. 1.7. It would help to agree that process in advance but > I have no strong opinion either way. > > > Richard Hattersley > Expert Software Developer > Met Office FitzRoy Road Exeter Devon EX1 3PB United Kingdom > Tel: +44 (0)1392 885702 > Email: [email protected] Web: www.metoffice.gov.uk > > -----Original Message----- > From: CF-metadata [mailto:[email protected]] On Behalf Of > Jonathan Gregory > Sent: 13 March 2014 17:24 > To: [email protected] > Subject: Re: [CF-metadata] Editing/publishing workflow > > Dear Jeff > > > Present CF Conventions policies require that all changes be > > provisional, and marked as such in the document, until determined to > > be permanent at a later time (this determination has never been made). > > That's the meaning of all the pink and yellow highlighting in the > > document at cf-pcmdi.llnl.gov. > > Yes, this is a issue. As Richard said, it doesn't matter how it is marked. > The problem is that all changes, however old, are still marked as > provisional, as you said. This is (a) a bit silly and (b) a nuisance as > regards legibility of the doc. The aim of provisional status was to allow > time for people to try out the change, in case a logical flaw was discovered > which hadn't been fore- seen at the time of the proposal. This was because of > the concern that many or most proposals concern data which has not yet been > written, so the metadata being proposed can't have been thoroughly tested. It > was supposed that some tests, using specified software, would be used to > demonstrate the new feature was "working", but no-one had time to work out > the details for this. > > I'd like to propose changing the rules. That's something the conventions > committee can agree, I believe. I would suggest the simplest possibility, if > we wish to retain provisional status, is to specify a time. We could say > that, after one year from acceptance or when the next version of the > conventions document is published, whichever is later, a change becomes > permanent. What do you think? > > Cheers > > Jonathan > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
