Acta Cryst. (1991). A47, 655-685

Concluding remarks

Crystallography, along with other computer-intensive disciplines, has entered an era in which the archiving and electronic exchange of data are of paramount importance. It is these basic needs of storage and transportability of data in a machine-independent form that have driven the development of CIF. The CIF Core Dictionary provides a set of data names, data items and definitions that are fundamental to crystallography. Future versions of the Dictionary will contain extensions to this core that cover data items of importance in more specific areas of the subject, e.g. powder diffraction, macromolecular crystallography etc. Developments parallel to those of CIF have led to the definition of a standard molecular data (SMD) format (Barnard, 1990) for the exchange of chemical connectivity and reaction data. SMD addresses the need to transfer data between databases and the various software systems for molecular modelling and synthesis planning. Since there is an overlap of information between CIF and SMD, it is hoped that some degree of integration can be achieved between the two formats.

The provision of a common standard format for machine-readable submissions to Acta Crystallographica and to the crystallographic databases has been a particular aim of the CIF development. These submissions require only a restricted subset of CIF data names for manuscript preparation, many of which can be generated automatically. We would encourage those who are responsible for the development of crystallographic structure determination packages to provide output CIF files as soon as possible. Further, we envisage that software tools will rapidly become available to assist in the upgrading of a program-generated CIF to publication standard. The submission, processing and publication procedures for CIF manuscripts directed to Acta Crystallographica will be announced in the November issue of Section C [Acta Cryst. (1991), C47, 2266-2275]. The announcement will indicate those CIF data items that are normally regarded as essential in manuscript submission. The announcement will also indicate how authors without electronic mail or diskette facilities will benefit from the new procedures.

There is no doubt that the standardization of data exchange formats is overdue. Existing approaches are inadequate because they sacrifice portability, flexibility and extensibility for computational efficiency. Today's and tomorrow's computer technology relegate the latter consideration to a much lower priority. The STAR File, and its specific application to the CIF, are seen as forerunners in the development of new tools for local and global data exchange.

The authors wish to thank the IUCr Executive, members of various IUCr Commissions, the IUCr Working Party on Crystallographic Information, and a number of other crystallographers for their constructive comments and active encouragement during the course of this development. In particular we acknowledge the input and support of Enrique Abola, Mike Dacombe, Paula Fitzgerald, Howard Flack, Richard Goddard, Carl Krüger, Brian McMahon, Ted Maslen, George Sheldrick, Rolf Sievers and Jim Stewart which contributed directly to the CIF construction. Without this cooperation the relatively swift completion of the central core of this project would not have been possible. We are indebted to Hazel Woodley (Cambridge) for her careful editing of the many revisions to this manuscript.

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Copyright © 1991 International Union of Crystallography