Finding nemo.dic

[Brian McMahon]

Dear Colleagues

I try to manage the "official" CIF dictionaries in an orderly way,
in part through maintenance of the CIF dictionary register
   ftp://ftp.iucr.org/pub/cifdics/cifdic.register

This file (in CIF format, naturally) lists the file names, versions
and URLs for COMCIFS-approved dictionaries, for DDL dictionaries and
for some "local" dictionaries used by the IUCr journals office.

By now, we are seeing a reasonably large number of reserved prefixes
for individual developers (or software applications) - see
http://www.iucr.org/resources/cif/spec/ancillary/reserved-prefixes .
Increasingly, in the editorial office, we are having correspondence
with such developers, and we would like to encourage them to make
available compilations of local data names in CIF dictionary format,
in order to reduce the number of warnings emitted by CIF editors such
as publcif and encifer, and - in principle - to allow normal
dictionary-based validation of such items. To encourage them further,
I would be willing to provide an area on the IUCr ftp server where we
could archive such dictionaries, and make them known through the
cifdic.register file. Details of how this would work in practice are
elaborated below.

I'd be interested in your thoughts on this. If you are in favour, I
could advertise the availability of such a service through the
cif-developers list.

Best wishes
Brian

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Below is an extract from the suggested extension to the register.
"Nemo", of course, is an entirely hypothetical example.

data_validation_dictionaries
  loop_
    _cifdic_dictionary.name
    _cifdic_dictionary.version
    _cifdic_dictionary.DDL_compliance
    _cifdic_dictionary.reserved_prefix
    _cifdic_dictionary.date
    _cifdic_dictionary.URL
    _cifdic_dictionary.description

##############################################################################
# COMCIFS approved dictionaries                                              #
##############################################################################
  cif_core.dic    .    1.4.1   .    .
      ftp://ftp.iucr.org/pub/cifdics/cif_core.dic
      'Core CIF Dictionary'
  cif_core.dic   1.0   .   .    1991-09-20
      ftp://ftp.iucr.org/pub/cifdics/cifdic.C91
      'Original Core CIF Dictionary'
 . . . . . . .   # additional "official" CIF dictionaries
##############################################################################
# Private dictionaries (re)distributed by the IUCr                           #
##############################################################################
  cif_iucr.dic   .   1.4.1  .     .
      ftp://ftp.iucr.org/pub/cifdics/cif_iucr.dic
      'Private data items used by the IUCr in journal publishing'
  cif_iucr.dic   1.1.1   1.4.1  .     2011-07-04
      ftp://ftp.iucr.org/pub/cifdics/cif_iucr_1.1.1.dic
      'Private data items used by the IUCr in journal publishing'
 . . . . . . .   # the above section already exisit for local IUCr dictionaries
##############################################################################
# Private dictionaries maintained by third parties but with archival copies  #
# available through the IUCr                                                 #
##############################################################################
  cif_nemo.dic   .   1.4.1  .     .
      http://www.nemo.com/cif/dictionary/cif_nemo.dic
      'Items used by the NEMO software package'
  cif_nemo.dic   1.0   1.4.1  .     2010-12-25
      ftp://ftp.iucr.org/pub/cifdics/extras/cif_nemo.1.0.dic
      'Items used by the NEMO software package'


My comments on this proposal:

(1) Such external dictionaries would be stored in a specific area of
the IUCr FTP/web site; we would try to ensure that access to this area
involved sight of a disclaimer that the contents were the
responsibility of the individual developers and did not represent any
IUCr endorsement of crystallographic practices that they reflected.

(2) Files accepted for archiving in this area would be subject to the
normal dictionary sanity checks that I apply to the existing
dictionaries; and they should contain data names that properly
implement a registered reserved prefix.

(3) In general, the register should also point to a dictionary without
version number available from the web or ftp site of the third
party. This should be a URL that represents the most current version of
the dictionary. In this way, developers can update their local files
at any time without depending on deposition at the IUCr and associated
updating of the register. However, specific versions will be advertised
as being available from the IUCr, thus providing a long-term archiving
facility which might be useful to such third parties.

(4) Participation remains completely voluntary.

This scheme is intended to be compatible with the suggested use of the
AUDIT_CONFORM category in the core CIF dictionary, and to remain in
the spirit of Chapter 3.1.8 of International Tables G on "Management
of multiple dictionaries" (http://it.iucr.org/Ga/ch3o1v0001/sec3o1o8/).

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